<a href=showthread.php?s=&postid=6865995#post6865995 target=_blank>Originally posted</a> by xusnavy
Koden, I recommend buying the Leviton brand. I've tried the portable ones that plug-in to the outlet and found them to be too sensitive for my lights (they would trip everytime I turned my lights on). However, they do work well for my power heads and pump.
I suggest buying two Leviton in wall units along with two electrical boxes (you can buy all this at Home Depot). Wire them separately, so that you have two separate GFCI boxes. Then, plug your lights and at least one power head in one GFCI box, and your pump, heater, and the remaining powerheads/electrical items in the other. This way, if one of the GFCI units accidentally trips, you will still have other pumps/powerheads working on the other separate GFCI.
If you install the GFCI into the wall, every socket that is wired down from it will be protected. However, it also means that there is a greater chance that it may accidentally trip as well.