Posted: Sun May 11, 2008 7:24 pm
Hardness, alkalinity and pH are things that you need not worry about. Ammonia, nitrite and nitrate are the things you need to control.
It all starts with ammonia (turtle waste). Your filter, if it's working properly, converts this to nitrites, then the final conversion is to nitrates.
The filter needs to have nitrifying bacteria built up in the bio media (rings, stars). The bacteria is what "cycles" the waste. Once it gets to the final stage (nitrates) you have to do a water change to keep it under control.
Did you change out all of your media? When you change your water do you use a water conditioner to remove the chlorine? Chlorine will kill the bacteria in your filter. Do you rinse out the sponges and bio media in used tank water or conditioned water?
Nitrate is pretty harmless, but can cause the algae to build up in the tank quickly. 60 PPM is pretty high, but not all that unusual for a turtle tank, especially with multiple turts. To pull down nitrates quickly, do a 50% water change, wait about an hour or so, than do another 50% change. Unless your sponges are really dirty or your bio media is clogged, the level should come down to somewhere in the 10-40 PPM range.
Ideally, ammonia and nitrite should be at zero. If not, you may need to look at the media or maybe use a larger filter. The numbers you show tells me your filter is working, just not as well as it should.
"Make it turtle proof, and they'll build a better turtle."