Hi Dumb Guy,
This design is not really new, at least not in my opinion. It is really a modification of the EuroReef design except that with the EuroReef, the feed pump is also the venturi/aspirating pump.
But I think the idea is good because I have run a very similar DIY design for several years now. A skematic of mine can be seen on the Reef Central on line magazine in the June edition. The main difference is that you maintain level by adjusting the overflow pipe height while I use a valve.
There are some other differences too. Most are due to some issues that will arise when building the design as you have shown.
1) If the pump is very low in the skimmer, it will run under a constant pressure created from the height of the water column in the skimmer. A small pump with minimal suction capability will not aspirate very much air into the water, especially if the skimmer is very tall.
2) If it is to be gravity fed, the top of your tank will need to be higher than the top of the skimmer. This will limit the height of the skimmer depending on where the skimmer is located relative to the tank.
3) In a power outage, the air intake to the skimmer will leak out water until the water in the skimmer is below the level of the venturi air inlet. This can be remedied by connecting air line tubing to the venturi air inlet and securing higher than the skimmer water column height.
4) The venturi discharge back into the skimmer column should be at least 6 inches above the point where the water enters the over flow pipe or the over flow will contain many bubbles.
5) If your overflow control maintains level as a simple overflow and then drops back down into a sump as a free fall, it will be very noisy. You could pipe the return down to the sump and put a vacumm breaker in this pipe to prevent siphoning. Such a design does put bubbles back in the sump and obviously begins to add complexity as well.
I made mine using a mag 950 as the aspirating pump and placed it higher in the skimmer column so that it has a very easy time pulling in as much air as desired. The return (from the aspirating pump) going back into the skimmer column is then returned near the bottom of the skimmer through an internal pipe. I chose to use a separate pump to feed the skimmer so that I could control the water throughput independent of the aspirating pump, as is true with suggested design. This means I must control the water height in the skimmer column by either throttling the feed or the discharge from the skimmer. But the valve is really no worse than having to set the adjustable pipe as in your design. With my skimmer, which is 6" in diameter about 6 ft tall, I also have to have enough room in my sump for an extra 5 gallons of water which will drain from the skimmer during a power outage. Your design removes this problem.
I think you should be able to make a very effective skimmer using your design as long as you account for the few pit falls I have mentioned. Maybe someone else will see some other issues, but i doubt it since mine seems to work quite well.
Good luck, Mutagen
