[ChuckG]

Originally Posted by DaveK

The top off or water change water can really be done just about any place in the system. I happen to use the return sump area.

I disagree with this one.
You wouldn't want your ATO placed in the display tank. The display level won't lower until your return area of the sump runs dry.
You don't want to place the ATO in the input section of a sump as the surface water is generally very agitated and would make any kind of float bounce around like crazy.
The best place for an ATO would be the return section of the sump where the surface water is generally quiet. This is also where you will see the results of evaporation first. To me - that makes it the ideal location for an ATO.

Originally Posted by ricosuave

Yeah, I was thinking of using a total of 4 - 250w MH with 8 x 65w PC actinics. Of course DIY. Instead of canopy or tank mount I am thinking of suspending them with some sort of manual hoist/chainfall to raise them for maintenance. Is that too much light, remember this tank that I am looking at is just over 30" tall

I don't believe 250 watt MH's will be enough penetration for the lower area. I think you'll have to use 400 watters as a minimum.