I am a first time RES owner and just bought a small 4-5 inch turtle from the pet store. Just today we noticed a red substance along the bottom corner of the tank and don't know if it's blood or algae. I cleaned the tank last week and it needs to be cleaned again. I bought a heater for the tank as well as a thermometer and it's a steady 78 but the turtle just hasn't seemed happy since I put the heater in (last week). It hasnt been basking since the last tank clean.