I have not done the math, since tere are still some details...
Especially the pool filter that I still look for a solution, I'm talking to Premier in Bangkok for a better liner, 1 mm thick, one piece, I'm wondering about removing all the river rocks, redoing the lining and re-putting the rocks, or simply putting the liner on top and bringing new rocks...
Right now, I'm rather busy renovating a house in Chiang Mai... new thread.