Thread: Cleaning a concrete fish pond

It doesn't take long in Thailand for a green look to spread throughout the pond.


The filter is rather dirty.

Why do you need to clean it out? I had a large fish pond in Saipan and never did anything but clean the filter for the six years I lived there. And the filter was just six inch long piece of perforated pipe with some window screen wrapped around it.

Here is the worker cleaning the coral rocks. We tend to replace these rocks every 6 months or so.


The fish have been safely moved. We lose a few small fish everytime this is done, but as of yet I do not know how to prevent this.

Originally Posted by buadhai

Why do you need to clean it out? I had a large fish pond in Saipan and never did anything but clean the filter for the six years I lived there. And the filter was just six inch long piece of perforated pipe with some window screen wrapped around it.

The wife asks the same thing. I suppose that I just get tired of looking at the green water.

The pond is now empty.


And so is the filter tank.

Scrub out the pond.


Scrub out the filter.

Originally Posted by hillbilly

The wife asks the same thing. I suppose that I just get tired of looking at the green water.

Now I see why; you have Koi. Koi eat a lot and dump lots of nitrogen in the water which causes the algae bloom. You could try lots of water plants, but the Koi will eat them unless you provide some sort of barrier.

Or, you could switch to Comets (a cross between Koi and Goldfish) which are not so voracious and which will coexist with plants which will happily consume the excess nitrogen. Comets won't get as big as Koi, but they will get up to about 6 inches or so and look OK in your size of pond:

Replace the cleaned coral rocks, add some chemicals and begin to fill up the pond.


Almost filled. The blue look disappears in about 3-4 days.

Thanks buadhai, you have answered some questions that have been on my mind for about 2 years now.

I think Comets might be the way to go!

Here's an overhead shot of my old pond:



The main pond is to the left. A short stream passes under the bridge to a tiny pond on the right. This is where the pump is. The water is pumped all the way to the main pond where it re-enters like this:



The "stream" is actually long, narrow pond filled with 1/2" gravel. This is the real filter and where nitrogen not consumed by plants is broken down.

[Sorry for hijacking your thread HB.]

Originally Posted by buadhai

[Sorry for hijacking your thread HB.]

Your not hijacking my thread! Please carry on as I love my fish ponds.

Don't be so modest budhai. Everyone check this out...

https://teakdoor.com/gardening-in-tha...in-saipan.html

Originally Posted by hillbilly

Originally Posted by buadhai

Why do you need to clean it out? I had a large fish pond in Saipan and never did anything but clean the filter for the six years I lived there. And the filter was just six inch long piece of perforated pipe with some window screen wrapped around it.

The wife asks the same thing. I suppose that I just get tired of looking at the green water.

Well, just do what I do with the swimming pool. Dump half a cup of chlorine in it. Sorted.

I had never thought of that! It would probably cut down on my fish food expenses...

what about snails and bottom dwelling fish - i think catfish will help eat the algae....

Originally Posted by kingwillyhggtb

what about snails and bottom dwelling fish - i think catfish will help eat the algae....

Both might help a bit, but you really need plants to soak up all the excess nitrogen. Some people block off one section of the pond from the Koi so that plants can grow there. Another solution is something like lotus in pots the rim of which is just above the surface of the water, keeping the fish out. A couple of healthy lotus will use a lot of nitrogen and provide some interesting flowers as well. Since their leaves are aerial the Koi can't get at them. The pots keep them out of the roots which they will otherwise devour.

Another thing to do is provide more shade so less sunlight hits the water, limiting algae growth a bit. Floating plants (pistia, duck weed or even lilies with floating lily pads) can prevent sunlight from getting to the algae, but Koi eat them up pretty fast.

Or, you could switch to Comets (a cross between Koi and Goldfish)

Nothing of the sort. Comets are a long finned goldfish.

Koi will not specifically cause algae blooms in your pond.

oops, just noticed this thread is two years old!

Hows the pond HB?

Originally Posted by kingwilly

i think catfish will help eat the algae....

Catfish don't eat algae, they're meat eaters. Tilapia would do the job through

Originally Posted by bkkmadness

oops, just noticed this thread is two years old!

Shit...me toooooo....

You guys may have noticed, my fish pond tends to be just a different than Daltons.

Oh yea, my fish pond is still going strong.

Originally Posted by bkkmadness

Or, you could switch to Comets (a cross between Koi and Goldfish)

Nothing of the sort. Comets are a long finned goldfish.

Koi will not specifically cause algae blooms in your pond.

Koi
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Cypriniformes
Family: Cyprinidae
Genus: Cyprinus
Species: C. carpio

Goldfish
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Cypriniformes
Family: Cyprinidae
Genus: Carassius
Species: C. auratus
They are in fact in the same family and merely specially bred carp.

Interesting argument. Keep in mind that everything on the internet is not always true.

Old or not, it's a useful thread for me so I'm glad that it's come to the surface. My pond has a similar filter arrangement to hillbilly's. The pond being a long, narrow horseshoe shape, cleaning it is a pig of a job to empty and the clean water soon turns green again. Still it's fairly new and we are still experimenting with fish and plants.

One question I would like to have answered is how can I test the quality of the water and what should it be? We use mains water but have a borehole. The water from the latter is said to be too mineral laden for the fish but it's cheaper so I would like to know what I would have to do to make it suitable.