SO, yes, u read that right, I have a 11gal cube on a radiator in my room cuz there's nowhere else to put it, parents won't let me, so what can I do to keep the temp constant, can I just have my intank heater stay at 69*, or should I do twice a week COLD ahh water changes?(I have 2 clowns, and I'm getting a rainbow btanemone, noopsyche k7mini)