Adrian my water seems to be much like yours yet, I must use a calcium additive
or I will see deformities. In the hatching tank I don't change the water for at
least three weeks after hatching. I do regular water changes once/week on all my
tanks. About 40%. I have tested my 65gal tank which contains a goodly number of
large fish and the ph is the same before and after water changes, so I would be
surprised if ph is causing these problems. I rarely see it occur in my other
fish. I will check that possibility though.
This problem may begin in my hatch tray. I use tupperware sandwich containers
which I float in a tank and I provide air. I change water daily until shortly
before hatch out. Again I can't see that a ph drop is occurring here. But I will
check this possibility.
Should I test the water for some specific type of calcium or will a broad range
result tell me if the "critical" ingredient is low or adequate?
What do you feed your fry and fish?
Chris