equipment placement

[Dale]

I've had a coralife 125 superskimmer on a 75/50 (100G. nominal) reef for a year now and am very pleased with its performance.

I can't tell from your schematic, is the skimmer hang on back or in the tank?
One problem I found with the HOB design is that, if the collection cup overflows, it will flood the floor and suck a lot of water out of the display (the pump sits low in the tank). You can partially avoid that by connecting a hose to the nipple on the bottom of the cup and drain it into a bigger container but, if the skimmer does continue to overflow, it will still suck a lot of water out and probably flood that container too.
I quickly saw the benefits of a sump
Another option, if you can't/won't do a sump is to put a large overflow box in the display and hide the skimmer in it.
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Yamaha XV1100