I didn't thoroughly read what Bobby (biggun110) wrote, but if it was mentioned about the nitrogen cycle, that is an important concept to consider. In a nutshell, critters produce toxic wasteproducts (ammonia). There is bacteria (nitros-amonas, for grins and chuckles) that breaks down the ammonia into still toxic nitrite. Then nitro-bacter bacteria breaks down the nitrite into realtively harmless nitrate. But this takes time, several weeks, in a typical fish tank. When people buy a typical 10 gallon set up and are bent on putting fish in there the next day, after adding Declor for the chlorine, they are setting themselves up for failure, because the Nitrogen Cycle hasn't had the opportunity to do its thing and the tank is then overwhelmed with toxins. We see the cloudy water and that's the "good" bacteria beginning to work, but it is too much too fast. The "good" bacteria forms on the filtering medium and it just takes time. So normally, what one does is buy one fish or turtle or... and let it produce ammonia so it gets the bacteria going. A little waste is what we want - not too much. There are also test kits that can be purchased to monitor the progress of the cycle.

So basically, let the tank get through with the nitrogen cycle first, with just the turtles, and then slowly add other living things.