so i have 2 RES turtles and i just got a 75 gallon tank for them. its 21' high and i filled it up abaout 17' of water. is this to much water for them? also i have 2 rena heaters for a 50 gallon in there set to a temp of aobout 78 is tis a god water temp? for my last question is i have a fluva 4 plus filter in there do i need more then one or no?