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Thread: An Isaan Pond

  1. #176
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    Many thanks for all the advice... I'll address some points below. But first...

    After only a handful of losses during the day yesterday I was quietly optimistic that the new temporary aeration system had solved the problem. I left it on overnight as the water O2 levels are known to decrease during the night hours, and I walked down to the pond first thing this morning full of hope.

    To this...







    There were dead fish everywhere... even under these plants where the tilapia used to spawn...



    Here's my daughter doing her unhappy face...



    This morning I hooked out 63 dead fish... all tilapia and some really big ones. A couple of months worth of fish an' chips. We've lost about 140 fish altogether now.



    After the dog walk, and then hooking out all the dead fish, I was cleaning out and feeding the chickens (the gardener usually helps with this, but since there is currently some confusion with my daughter's school as to whether or not I should be in 14 day coronavirus self-quarantine after visiting Singapore last week, I decided it was better for the gardener to do the school run today), when my wife, with her uncanny ability to arrive at a scene about 3 minutes after all the work has been done, came to see how things were getting on. She told me that she has a friend with a fish farm who she's told about our dead fish... "Oh yeah...", says I, wondering why on earth she hadn't shared this with me earlier (about 6 years earlier) ... and her friend had told her that it sounds like we have a problem with the water... Unfortunately I didn't respond as she'd hoped to this vital piece of information, and much to my regret my sarcastic side came out. The upshot being... the wife's gone down to her mum's today... so it's just me and the gardener left to solve this problem!

    Anyway, supposing that my wife's genius fish-farmer friend is correct and we do indeed have a problem with the water... this is what I can't understand.

    1. Why now? The weather isn't particularly hot and we've been using the waterfall more lately than is usual.
    2. After not losing many fish yesterday afternoon, why so many during last night... with the aeration system on. Usually there is no aeration at all during the night with no problems.
    3. Could it be that these fish died previously but have only just floated up to the top? I don't think this is the case as a few looked fairly fresh and will no doubt end up in the gardener's pla ra.
    4. If indeed we have had an algal bloom with associated loss of oxgygen and rising pH levels... will this correct itself or should I attempt to alter the pH using chemicals? I think this is a dangerous approach to be honest.

    Klondyke... the pond was built using a concrete lining in 2012, 7 years ago. I've since read that I should have sealed the concrete with something to prevent lime leaching into the water, but after all this time I can't see that being the cause. Last week I did in fact use some cement on a new small area of rockery by the side of the waterfall... but only a very small amount of cementy water ran into the pond and I really can't see that having an affect on such a large body of water?



    I've just had an email from Lazada stating that my pH measuring kit should be arriving today. So long as it's not Kerry I should at least be able to test the water by this afternoon.

    Helge and Dave above... thanks for the advice and my plan is to install some kind of low noise system that can be on 24 hours a day... either hosing with lava stones on the end (which we use in the catfish tank) but on a big scale, or more likely something like Dave's Youtube system with a network of perforated pipework at the bottom of the pond through which compressed air can be pumped.

    And sorry about your weather Helge... I should be starting up in Norway again next month and it will be quite a shock.

    CalEden... thanks for that. In 8 years, this Monday was only the second time that I've pumped out the sludge form the bottom of the pond. As you say, this will be nitrate rich fish shit and rotting plant matter - can't be healthy for the pond. My new regime will be to do this every 2 or 3 months. It's a two man job, but only a morning's work. I can pump it into a pit on wasteland outside our house and then use it for fertiliser on the veggie plot.

    RE overcrowding... much less so now! A few uyears ago I became concerned at how overcrowded the pond was becoming due to the tilapia (pla nin) breeding. I introduced a few pla chon (snakehead), a predator, that seemed to solve that problem as we have no fish fry now. A couple of the dead tilapia I've hooked out have only been half a fish with the tail end missing. I think we now have some very big pla chon in the pond, which will become another problem... also, I have seen pla chon fingerlings...

    As you say... a time and money pit in the making...
    Last edited by Mendip; 26-02-2020 at 09:30 AM.

  2. #177
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  3. #178
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    ^ So...am I to understand The Gardener did it in The Pond with Paraquat?

    Or... The Wife did it in The Pond with Peas?

    We have a bottle of Paraquat locked away in the workshop, and I also have a stash of Peas in the freezer. Easy to see if either has been tampered with...

    Motives? Huge source of fish for pla ra now available which puts the Gardener and Wife right up there in the frame... but who would eat pla nin poisoned by Paraquat?

    And are Peas even bad for fish?

    A lot to think about...

  4. #179
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    We sat and pondered where it had all gone wrong... (pun intended!)

    The waterfall and pump going full belt... the sun out, so all those plants and algae should be photosynthesising away... and thus the water should be nicely oxygenated and circulating.

    We've only lost two more fish this morning, and both looked very with one covered in sludgy mud. I reckon they were long dead but had just floated up to the top once buoyant with gas. (even the gardener turned his nose up at these)

    But... the problem is... how to stop another mass death tonight when the O2 levels decrease. What more can I do in the short term apart from keeping the waterfall and pump going through the night?


  5. #180
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    The pH testing kit arrived at last.

    Before testing the water I stirred up the margins with a stick and thick clouds of green-coloured sediment came up. I would have expected brown muddy sediment on the bottom of the pond, but not green (although I have never really looked into this before... it's only since we've had the problem.



    A green scum has collected in some areas now that the water is circulating...



    And where the pump is blasting out water (to hopefully aid aeration) there is an obvious difference between very opaque green water and less green water at the edge of the flow... (but not so obvious in the pic unfortunately).



    The pond water has always been green, but I've never previously noticed it so opaque green looking as it is now. My feeling is everything points towards an algal bloom, with dead algae coating the pond bottom, rotting and using up all the oxygen.

    Before testing for pH I took this pic and the amount of suspended green algae in the water is very obvious.



    And the pH...



    This looks bang on 8.2 to me, so slightly high but well within the quoted comfortable limits for pond fish of between 6 and 9. At least the wife's last bottle of vinegar is safe.

    So what to do? Any ideas. I can't really see that filtering the water in the short term is feasible for such a large pond, and besides, I think the problem is the dead algae sediment on the bottom of the pond, not the live algae suspended in the water column. Will this sort itself out with the algae rotting away eventually, and then we could restock?

    How to stop it happening again... without becoming an all encompassing project and without costing a small fortune. After all, this was supposed to be hobby that also provided a few fish for tea, nothing more!

  6. #181
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    With what did you measured before pH 10? This tester is for swimming pool, it does not show more than 8.2, what still would not be bad for fish and people either.

    However, if you really have much higher pH up to 10, then it could be harmful for the fish. So, you should find a stationery shop that sells a pH paper with higher pH scale than 8.

    I am having this tubes too, however, no longer bother with the measurement, it does not have any influence on clarity of swimming pool water, just showing that you should lower your pH towards 7 in case you treat against algae with chlorine only since the chlorine is more effective with pH 7.2. That is the main income for the pool shops, chlorine and pH minus, daily headache and cost.

    With Copper Sulphur (and a bit chlorine) such problems fall out and the pH measurement either.

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    This project is proceeding to be much more complicated than it probably needs to be, Mendy....

    Best to ya in your attempts to "naturally" balance the make up of your pond water.

    Next go 'round, you might ask someone locally who has had experience with similar things.

    Just a suggestion. But you might reconsider the species of fish that you're forcing to survive in that particular setting - regardless of what you're doing/not doing to the water.

    Good luck.

  9. #184
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    You've got Jeff and Klondyke on the case now, so an answer can't be far away.

    And had you gone whom about there would be circling realities in the shift to realisation of mutual demographic.

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    Quote Originally Posted by Klondyke View Post
    Did you check pH?
    Quote Originally Posted by David48atTD View Post
    PH has to be monitored
    I'm fine, thanks. Really
    Quote Originally Posted by Chico View Post
    Upto until the 70's Australians referred to themselves as Pom's.
    Quote Originally Posted by Chico View Post
    Just asking the supposed teacher if he is a teacher,as anything more than ten syllables and he's fucked.

  11. #186
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    Many thanks for all the help... we lost another 5 during the day today so 68 for the day... a few months' worth of fish and chips (or my signature dish of poached pla nin with a couple of eggs in milk, which my daughter doesn't seem so bothered about).

    pH, or PH... you may feel fine but you were decidedly purple yesterday and today you are still a little 'high'...

    Klondyke... my first pH measurement was with the last of an ancient pool measuring kit, many years old, that disintegrated in my hands as I used it. I 'guestimated' the pH by using a scale on the internet after I'd lost the sample. As you say, the pool testing kit only shows a scale up to 8.2... but Phenol red is Phenol red... a higher reading will show a different colour indicator regardless, but maybe not reflected in the provided scale (which is, as you say, based on pools). At least, that is my understanding. It's just a coincidence that the pond water today directly coincided with a pH shown in the scale provided by the kit... 8.2. It was decidedly more purple two days ago... and I guessed at around 10. Maybe the two bottles of vinegar brought it down?!!

    Mr Dillinger... many thanks but it seems the pH is fine. Can you find a video about an oxygen crash associated with an algal bloom? Ya Dong compliant... ie. no longer than 2 minutes and in very simple language.

    HuangLao, or may I call you Jeff...? (I'm very mindful of my newbie status...)

    This is the first time in 7 years we've had a problem. While I take your point about raising suitable fish (like when I lived in Perth we had drought tolerant plants), but who wants to eat catfish fish and chips? That's the problem. The pla duk survive in stagnant ditches, yet they don't taste so good... I'm gonna persevere with the tilapia for the time being!

    Anyway, for tonight the waterfall and pump stays on... let's see what we have in the morning!

  12. #187
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    pH Crash:
    German standard for drinking water (and the Germans are very anxious) allows much wider range of pH: from 6.5 - 9.5.

    An Isaan Pond-trinkwasser-jpg


    Whether the fish would not survive what the man does?

    This is something what the pool experts - and their shops - do not like to hear. They insinuate that not only for the pool water but also for the human already the pH 8 is unhealthy. Whilst the sea-water is over 8, as well as the healing spa springs, even the mother's milk is over 8.

    And since our world ambiance is getting more and more acidic - and our body even more especially when consuming meat products - the medicine experts recommend to keep our organism rather near to pH 8 than 7.

    Although I have the pH measurement for swimming water, I have to admit that I had never checked the fish pond water (just mildly recirculated) where the 20+ kois have been residing over 10 years with almost no casualty.

    Back to the Mendip's problem: even if your pH measurement was old but showing pH10, it should alert you. Whether 8 is OK however 10 is really much higher, don't forget that the pH scale is logarithmic...

    Surely some kind of recirculation will immediately help. When the DaeWo submersible used (fixed a bit over the bottom) it should not disturb the neighbours.

  13. #188
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    Quote Originally Posted by Mendip View Post
    but who wants to eat catfish fish and chips?
    Erm....Jeff

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    Farang think/overthinking all of this.
    Uh-huh...

    To be expected.


  15. #190
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    It may be that you can trace the source to some recent event like something entering and emitting gas.

  16. #191
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    Quote Originally Posted by HuangLao View Post
    Farang think/overthinking all of this.
    Uh-huh...

    To be expected.

    You got a fish pond at home Jeff, or does the winter ice and snow make it impossible?

  17. #192
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    Quote Originally Posted by Mendip View Post
    This is the first time in 7 years we've had a problem.
    In hot summers, I often heard the term "buttom up" regarding lakes, that got the sickness, that your pond has.

    In nature, it means a fresh start after some time of settling. We haven't got time for that.

    What will plan b be ?

    Snails ? Mussels ? Something to dig in the fishshit and surplus fodder
    I'll go with mussels this year

    Have you tried the Asian Pest, you know, they float around in the rivers of Thailand, and are good for water filtering and pig fodder.
    Banned as invasive in Denmark now
    Quote Originally Posted by HuangLao View Post
    Farang think/overthinking all of this.
    Uh-huh...

    To be expected.
    Ofcourse
    Mendip and I have sensitive souls

  18. #193
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    Prior to or during the die off did you observe fish at surface/edges gulping air? Sure sign of oxygen depletion in water. If not
    I think you have a nitrate problem. The second article goes into more detail. I had trouble copying it, use your curser to high light to see clearer. The links are at end of each article. Pumping the sludge out was right thing but might have elevated nitrate levels in short term by disturbing/distributing.

    Maybe some those new fish you introduced to the pond been diseased or have parasites? Did they come from China? Could be Corona 19 virus. You need to outfit your fish with fish masks to stem the spread.

    Water Quality

    Water quality and the oxygen level in the water are the two most important factors for healthy pond fish. Water with low oxygen levels or high ammonia, nitrite or nitrate levels creates a potentially lethal environment. With water-testing kits available at pet stores, you can test your pond water. Gather a small sample of water, add drops of testing solution to the sample according to the instructions on the label and determine the water quality based on the resulting color change. A pH reading between 7.0 and 9.0 is acceptable for a fish pond. Ammonia and nitrite levels should be at zero, and the nitrate level should be less than 50 parts per million. If your pond is measuring above acceptable levels, you should change at least 30 percent of the pond water to freshen the pond. Fish in ponds with low oxygen levels may stay near the surface of the water in the early morning hours and have reduced appetites and activity. If oxygen in the pond is extremely low, aeration with a mechanical device such as a pump or fountain is necessary.

    Water Temperature

    Severe or sudden water temperature fluctuations cause stress to pond fish, making them more susceptible to disease and less able to cope with other problems that may occur in the pond, such as low oxygen levels or increased ammonia levels. Frequently, the stress is too much for the fish and is fatal.


    Overcrowding and Overfeeding

    Overcrowding and overfeeding, two common causes of pond fish death, create lethal situations by reducing the amount of oxygen available and by increasing the amount of waste, which then increases the ammonia and nitrite levels. Prevent overfeeding by removing any food left after five minutes. If the ammonia and nitrite levels rise above zero, the pond is overcrowded.

    Algae

    A large amount of pond algae can kill pond fish. As a byproduct of photosynthesis, algae creates oxygen during daylight hours. Algae uses oxygen during the nighttime, which can deplete the pond’s oxygen supply if the algae blooms are large enough. In addition, large algae plants that die suddenly may be lethal to pond fish because the decomposition process further depletes the water’s oxygen.

    Disease

    Though sometimes stress itself kills fish, more often it reduces the natural ability of the fish to overcome bacteria and viruses in the water. Signs of fish disease include reduced eating, abnormal swimming or erratic motion, sores, blisters, bulging eyes, spots or growths on the body and discoloration of the fins or body. Keeping your pond clean, well-aerated and correctly stocked helps prevent the common causes of pond fish death.



    https://animals.mom.me/why-are-my-pond-fish-dying-12333600.html




    Fish die as a result of a wide variety of natural and unnatural causes. Fish may die of old age, starvation, body injury, stress, suffocation, water pollution, diseases, parasites, predation, toxic algae, severe weather, and other reasons.A few dead fish floating on the surface of a pond or lake is not necessarily cause for alarm. Expect some fish to die of old age, injury, winter starvation, or even post-spawning stress in the springtime. However, when large numbers of fish of all sizes are found dead and dying over a long period of time, it is necessary to investigate and determine the cause.Sudden, large fish kills in ponds are often the result of fish suffocation caused by nighttime oxygen depletion in the summer. Fish kills from oxygen depletion usually occur in the early morning hours (at dawn) in very rich (green water) ponds following: (1) the die-off of a large algae bloom, (2) the decay of water weeds after treatment with a herbicide, (3) the turnover of oxygen-poor bottom waters following a thunderstorm, (4) the runoff of livestock waste and other organics after a heavy rain.Symptoms of oxygen depletion may include an abnormal distribution of fish gulping at the water surface or at the pond inlet or edges. Large fish may die first, but all sizes of fish are usually affected. The color and clarity of pond water may change and a foul odor may be released. Fish kills from pesticides, chlorine, gasoline, fuel oil, ammonia fertilizer, acids, and other toxic chemicals are not as common in private ponds, but can occur.In order to prevent fish suffocation in fertile ponds:

    • Do not overfertilize ponds.
    • Do not overstock fish.
    • Do not feed ducks or sportfish.
    • Fence livestock from the pond and upstream waters.
    • Prevent manure and animal waste runoff into the pond.
    • Use herbicides only in the Spring and Fall.
    • Treat only one-third of the pond surface each time with herbicide.
    • Install emergency surface aerators or pump-sprays.

    Water quality tests


    Water quality tests are usually expensive, complicated, and may be inconclusive. A number of water samples from the surface and bottom waters and from the pond entrance and exit waters are usually required to identify a problem. Moreover, because pond water quality may change rapidly (within hours), just determining that oxygen levels in the afternoon are adequate for fish following a nighttime fish kill may be meaningless. Fish farmers usually conduct water quality tests daily to establish the pattern of conditions in their ponds, but most private pond owners do not monitor their pond water quality.
    Fish Diseases and Parasites

    Fish are constantly exposed to a wide variety of diseases and parasites that occur in surface waters. Fish are subject to infection by disease-causing viruses, bacteria, and fungi. Fish are also parasitized by tapeworms, trematodes (grubs), nematodes (roundworms), leeches, and lice. Most of these organisms normally occur at low levels in farm ponds and in limited numbers on the fish. Some parasitized fish in a pond are not unusual. However, large numbers of infected fish are cause for concern since slow growth, sterility, stunted populations, and massive fish kills may result from extensive diseases and parasite infestations.

    Fortunately, fish diseases and parasites seldom reach epidemic levels, and sudden, large fish kills in farm ponds are rarely caused by diseases or parasites. Fish suffering from diseases or parasites usually die slowly, a few fish each day. Only in severe cases when fish are in poor condition, starving, crowded, injured, mixed with wild fish, or stressed by rough handling, low oxygen levels, high temperatures or chemical toxins, do diseases and parasites become a serious problem.Some early warning symptoms of fish suffering from disease or parasite infections are:

    • Discoloration, open sores, reddening of the skin, bleeding, black or white spots on the skin
    • Abnormal shape, swollen areas, abnormal lumps, or popeyes
    • Abnormal distribution of the fish such as crowding at the surface, inlet, or pond edges
    • Abnormal activity such as flashing, twisting, whirling, convulsions, loss of buoyancy
    • Listlessness, weakness, sluggishness, lack of activity
    • Loss of appetite or refusal to feed

    Fish exhibiting any unusual form of behavior should be closely examined for external signs of disease or parasites. Infected fish usually show visible sores, discoloration, bleeding, swollen areas, lumps, popeyes, small black or white spots, or other abnormal growths on the head, body, and fins. Sick fish look and act abnormal.Fish Kills: Their Causes and Prevention | VCE Publications | Virginia Tech




    Fish Kills: Their Causes and Prevention | VCE Publications | Virginia Tech
    l


    Sorry could not change print color. High light with cursor to see clearly.










    Last edited by CalEden; 27-02-2020 at 01:53 AM.

  19. #194
    Thailand Expat David48atTD's Avatar
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    ^ WOW ... lots to digest there.

    ---

    Mate, it could be a number of factors coming together.

    At the Fish Farm we usually only spin the aerators when there has been a day without wind.
    The rippling effect of the wind across the water is sufficient to oxygenise it.
    You can increase the oxygen saturation of the water coming out from your hose by putting an aerator cap on the end.


    Make your hose outlet look more like this as in maximise the surface area of the droplets and point them higher in the air.



    Given the size of the Pond it does seem overstocked.

    We only use monosex Fish to alleviate the issue of having fry and can control the stocking rate.

    The Ponds are drained (usually) to harvest the fish so the water gets fully exchanged at least once a year.

    Under our growing conditions, the grow time from fry to commercially viable pla nin is 9 months.


    CATCH AND EAT MORE FISH FROM YOUR POND!


    Make one of these simple nets. Can be as big or small as you wish.



    ... plus she is easy on the eye
    “Someone is sitting in the shade today because someone planted a tree a long time ago”

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    Quote Originally Posted by Butterfly View Post
    let me explain simply 100MB != 1GB RAM

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    as you know,back in the uk.trout lakes ACID RAIN was a big problem,so just a thought have you any industrial works nearbye or a busy road cars causing high omissions,eg.sulfar dioxide and high levels of nitrogen.

  22. #197
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    A free green for anyone who can explain to me how to use the 'multiquote' function!

    This morning I went down to the pond full of trepidation to find this...



    Only two fatalities last night! And Yogi can not only sniff out snakes and the neighbour's cat... he also seems to sniff out dead fish for me... he led me to both today.

    I think that this is good news... or could it be that after losing 150 odd tilapia there are none left?

    Last night I left the waterfall and the temporary pump on all night. The hose is still going 24/7 and the pond should be full again in a day or so. (Dave, I tried to put a nozzle on the end of the hose to create a bit of spray but the water pressure is low on that water source it just didn't work... but thanks for the suggestion...)

    The waterfall gives plenty of splash-back... something I'd usually try to avoid, but in this case an oxygenating bonus!



    And the pump must be adding a lot of oxygen... to be honest the pond water has probably never been so oxygenated before.



    Many thanks for the advice again!

    Helge... in the wet season when we (used to) get standing water around the house, there used to be thousands of big water snails - I guess their eggs lie dormant in the mud until the rains come. I used to collect these and put them in the pond, but they always disappeared. I've also bought bags of snails from the market before and released them into the pond, but they seemed to have disappeared also. I have no idea where to find freshwater mussels, but this weekend I'll go down to the market with my daughter and get a few bags for the pond. If nothing else I'll be making some good merit!

    CalEden... I've pretty much ruled out parasites or disease since there are no signs of anything on the dead fish, and also the fact that it's mainly the big fish that have died also points towards O2 deficiency. None of the recent fingerlings I stocked last week have been found dead. I don't think the new fish came from China, but then all the pla nin look the same! Just in case, they can self-quarantine in the pond for ever.

    Since we've had the pond I have always noticed the tilapia gulping air on the surface around dawn - I often sit with the dogs and have a cup of tea at this time while thinking how to occupy myself during the upcoming day in Korat. As the sun comes up, the fish have always disappeared... which I have since learnt is fairly normal since once the algae start photosynthesising the water should become oxygenated. But never before have we lost fish.

    I was fishing in the pond last weekend and noticed a lot of fish swimming near the surface and hugging the margins... and with hindsight they were obviously in distress due to lack of oxygen. My feeling is that we've had an algal bloom, and with so much algae producing CO2 during the night, the fish have become oxygen starved. Photosynthesis has saved the fish during the day. At least, it all fits with what has happened.

    Immediate measures to save the fish are the artificial aeration and we've stopped all feeding.

    To stop it happening again...

    1. Regular pumping out of the nitrate-rich sludge.
    2. Try to prevent overstocking (although it's now too late to prevent breeding by stocking with monosex fish). I must admit it's been a surprise to lose over 150 big pla nin, I didn't realise we had so many. I generally like to catch the fish using a rod and line for fun... but if Dave's net girl is available maybe she can visit? Preferably along with the aeration girl in the Youtube videos.
    3. I'm planning to set up some kind of permanent aeration system using perforated pipework along the bottom of the pond.
    4. At least annually I want to replace 30% of the water. This will be easiest done during the monsoons for quick refilling (if we ever get them again).

    And then there's pH...

  23. #198
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    I am getting very confused over pH...

    I used the pool testing kit (in Post 179 above) and it looked to be bang on 8.2. This is what I don't understand... does that kit only test between the available range offered on the kit's pH range chart? In which case, all I know is that the pond water pH is at a minimum of 8.2.

    This morning I tested some lime juice I squeezed for my lime and soda drink. Lime juice should be pH 2.8.

    My pool testing kit indicated it at bang on 6.8... so I think this must just be the lowest possible measurement of the kit, ie. showing the lime juice to be at a maximum of 6.8.



    I looked up some charts of the internet... and a completely different coloured pH range chart is shown.



    All very confusing. Any chemists out there? I don't think I currently have any idea of the pH of my pond water.

    As Klondyke has been suggesting, I have now ordered some Litmus paper (with range 0 to 14). I've also ordered a digital pH meter and TDS tester (thanks Fondles)... and also a test kit to measure ppm oxygen in the water...

    As I feared... this is becoming a time consuming and potentially expensive project.

  24. #199
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    Quote Originally Posted by Mendip View Post
    how to use the 'multiquote' function
    Highlight the text you want to quote. Click on the "quote selected text" in the lower left hand corner of the post.

    Highlight the next text that you want to quote and click on the "quote selected text".

  25. #200
    Thailand Expat

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    Can also multi qoute by pressing the button on the far right bottom.

    Quote Originally Posted by Butterfly View Post
    let me explain simply 100MB != 1GB RAM

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