Hi Militant. I'm trying to picture your explanation above. So if you're looking at the tank from the front, you will be able to see in both side AIO overflow sumps (for lack of a better description)? The light from overhead will spill into them as well I'm guessing, right?
Yeah, my plan is to leave both sides visible, but my "hood" (for lack of better description) will enclose the sides, with doors that can be opened or closed to reveal or hide the areas. I'm doing it this way because it is going into my home office, and if I need to ever bring my legal clients in, I want the tank and area to look as nice as possible!
I'm intrigued because thanks to you, I'm working on my own version of this. It's a great idea.
There are a couple potential snags in my tank though. First of all it's 24" deep. That will mean a long way for the light to penetrate and the water to fall into the overflow as evaporation lowers the water level in the AIO sumps. I think this could be controlled by having one pump with higher (or lower) capacity than the other. Suppose one sump were emptied (and therefore overflowed into) at 900 gph and the other at 1200 gph. I think the 900 gph sump level would drop with evaporation while the 1200 gph sump would remain at its equilibrium level. Does that make sense?
The extra depth in your tank does add a bit of a twist to the design. To handle the light issues, you'll have to either add some extra lighting, or just aquascape so that you'll have a lot of higher level real estate for light light corals to grow, and use the lower areas for low light corals, such as mushrooms, etc.
As for the pumps, that setup might help a bit, but with an AIO, your evaporation will happen all over the tank, so both chambers and the display area will all be evaporating. If I recall correctly, you can minimize evaporation due to overflows by keeping the chamber's water levels fairly high relative to the tank. If the water has to fall a long way (I'd say 3 or more inches) you get a lot more evaporation, since you have a lot more water exposed to air, giving even more water vapor a chance to escape.
I may abandon the double AIO sump idea in favor of a single sump at one end and just let it remain visible from the display side. After all, the fuge and all the effort that goes into filtration and circulation is a part of this reef business; why hide it?
That's the exact same debate I had when beginning the design. I decided on the double sump because it was more of a symmetrical design, and I could hide powerheads on both sides of the tank for a more random water movement. In the end, that's what finally convinced me to go with chambers on both sides. I agree, the filtration and the fuge are all parts of the business, but sometimes it's nice to see just the finished product! I'm leaving mine unpainted, but leaving myself the ability to hide it when necessary.
Thanks again for your thoughts and ideas.
You're welcome! Feel free to ask any other questions you've got, and I'll do my best to help out. You'll have to let me know which way you end up going with your tank!