Our lake is situated in Thailand , close to the Cambodia border . It was man made about 4 years ago with the base sediment being clay .
We filled it from a 65m Bore hole pump that took around 1yr + the rainy season here (total is averaging 10M litres but full would be around 16mLitres.
The catchment water is actually the same as the lake (high in hardness and alkalinity) BUT the PH is actually lower at 7.8 or thereabouts . I don't have the answer to this difference other than to think the catchment water is sat there in the dark, anaerobic with little to no Dissolved 02
We did build some huge concrete raceways which would have increased the Ph but these should have long cured by now (3yrs) .
I have also used quite alot of Aluminium sulphate to lose some of the clay turbidity, which has worked really well and lowered the Ph when adding it , but the Ph slowly creeps back up again .
The only other thing I can think of is we use air blowers to oxygenate the water to almost saturation levels and wondered maybe this has an effect on Ph ?
Livestock mainly . Out Ph seems to be on the very high end of keeping them happy . That and our suppliers grow out at around 7.4 so would also mean much less of a quarantine period .
