Rick, I have noticed a slight staining of the water but haven’t found it to be a problem. My baby tank is a 20 gallon and the piece of cork is 12″x8″ so it doesn’t move too far. I have used this setup for 3 different batches of babies and they have all loved the cork. I tried a ramp originally but the cork seems to be alot more popular. I have large pieces of flat cork in my tubs with my adults as well. They pile up really high on it until one knocks down the pile. In my largest tub which is a 70 gallon horse tub I also have built a wooden ramp with small steps ( strips of wood) and the end in the water is kept bouyant with 2 fish net floats. The whole thing is hinged at the top so that if the water level drops some from evaporation it still stays within reach of the dbts. It is also very popular with my critters. Vickie