Advice? big skimmers

How big is this system? I'm assuming this is an external skimmer since we are rating it at 1000gph? External skimmers should be ran at approx 1.5x turnover per hr of tank volume. Ex... 100 gallon tank - skimmer should be 150gph. Which means you'd be looking at 670 gallons to need 1000gph on a skimmer.

 

Need to be able to put enough air and water in it to get the skimmate above neck and into cup. The companies that make the skimmers do a lot of R&D to get the balance right. Not saying a 600 or 700 gph wouldn't work out. I would imagine that a 300 would fail tho

 

This is a volcano skimmer. It has a air pump right on the plumbing before the water enters the chamber from the recirculating pump. The guy that had it before ran a Mag 7 pump on it. Jay is planning on running only part of the day. Mostly he is just curious as to what will happen say when he shuts it down after 12 hours of use and the water drains back into the sump. Biggest worry was how to make the ATO function without dumping more water into the system when ever the skimmer kicked on. I suggested running both through the APEX on opposite schedule. So run the skimmer for 12 hours with the ATO off and vise versa. He was just wondering if there would be any other side effects other then running the ATO differently. There will be about 5 gallons that will drain back out once the pump kicks off.