i have a 75 gallon tank who's primary resident is a red ear slider turtle named Spike. i have recently successfully introduced fish to the tank (in the past, he has eaten them, but as he's gotten older, he's decided to share his habitat) so while i'm pretty experienced in the care of my turtle, i'm somewhat of a novice when it comes to the fish. after about a month of peaceful cohabitation, i came home one day this past week and all the fist where dead (9 guppies and 2 really cool catfish - very sad!) so i took a water sample to PetSmart (i've never really had to worry about the chemical composition of the water, for Spike - i regularly added chemicals for breaking down boilogical waste, etc and change the water on a regular basis) It turns out that the nitrite levels were OFF THE CHART from the turtle waste and my fish were the unfortunate victims of my ignorance. I have since rectified the chemical imbalance, purchased my own water test kit and additional chemicals to help avoid a similar situation in the future. I am planning on replacing my lost fish this week. My question is, how beneficial is a moss ball in absorbing excess nitrites and ammonia in the water? i have researched the impact on my turtle (minimal - the main concern is whether or not he will destroy it and it could clog my filter) and have not been able to find any definitive information on it's impact on nitrite levels and such. Anybody got any ideas or suggestions?