The CPRs broke siphon so often, they put out that air pump thing to counter balance the poor design. I had one when they first came out.
What trouble were you having with your u-tube style?
The issue is with how the overflow box is draining water into the sump, or at least that's my guess. The problem is that when the U-Tube is moved in any direction (not in or out of water, but left to right tilted along the top of the box, the amount of water that goes into the sump changes (the u-tube also has zero air in it). What this looks like is the overflow box (the black box within the tank) is completely full, or at least mostly full. The part of the overflow box on the outside of the tank may be half full with plenty of water going into the sump. However, if the u-tube is moved or adjusted, even by accident, the water level on the outer box to the drain will either get very low or very high, and the water in the sump will either get low enough to burn out the pump or have a level at 13+ inches. This process happens within a matter of under a minute. I can adjust the position of the u-tube along the top of the box, and the water in the sump will adjust as well. The problem is that it wont ever level out and stay consistent. It will lower until the DT overflows and the pump burns out, or it will raise in the sump until that overflows...slowly but surely. I have the system shut off now, and I have an ATO on the way, but this issue even renders an ATO completely ineffective! I have not had this issue until yesterday, but for some reason I cannot get this to work properly. I obviously cannot put any livestock in as the water level fluctuates too much, I can't track evap which would affect the salinity, and many other things as well. The overflow box is also rated slightly higher for gph than the pump, so I really don't understand why it would allow the water to be so low in the sump, as if the pump is out working it.
The Overflow is an ESHOPPS 800 and the pump is an EHEIM Compact 2000. The Sump is an ESHOPPS RS 100. The hose from the Overflow to the sump is whatever hose comes with the sump itself, and the hose from the pump to the return is 3/4 inch ID (what fits the pump).
The inside box is at a level that the water reaches about halfway up the teeth, maybe slightly higher. The pump is actually rated for a slightly lower gph rate than the sump. It's weird, if the u-tube is tilted left or right a little bit, or even moved, everything gets re-adjusted, and and this point, I haven't been able to find the sweet spot as to be able to keep everything level, it just goes up and up and up or the opposite. Even weirder is that it's going fine for over a week now and then yesterday when putting the glass canopy back on top of the DT, it bumped the overflow box a little then all downhill from there w/ the u-tube thing.
