Can anyone give us advice? Hus & I very new to this....cycling tank right now. Aquarium store tested water, said it's good, little high PH though. Got that under control. Last three nights, the temp in tank slowly increases after lights off. Heater is not lit up (does light up when in use). 3 nights ago was 79F now at 83F?!?!?!?!? Any knowledge would be appreciated. Thanks in advance PS fish are not doing well :iill