Hidden Closed Loop Intake
 

Okay... I've been thinking about this for my current tank build. I'm trying to go for the cleanest look possible. I don't want to try to have to hide a lot with my rock work. I don't like the fact that a lot of people put the intake of the closed loop at the bottom because I'm going to have a sand bed (I don't want to risk sand getting into the closed loop or oceans motions). Some people have the intake strainer on the back of the tank (but my tank is 2 sides viewable so there really isn't a back. I don't really want to have to service the strainer often if it's near the bottom. So this is what I've come up with. This way, you get more surface skimming, and the hole in the side is just to make sure that the flow can keep up with the intake. If I choose to ever not use the closed loop, it doesn't do the tank any harm. Any comments or suggestions? I think maybe 2 returns through the bottom and 2 from the top using an oceans motions 4-way.

http://i600.photobucket.com/albums/t...g?t=1237924803

My closed loop uses the overflow. Acctually, the CL pump is IN the overflow. :D

But your return lines of the closed loop are probably all at the top. If I have the intake in the actual overflow box, then water would go through my bottom return lines, siphon and drain the tank in a power outage right? At least up to the level of the drain in the overflow box. Mr. Alberta had that happen a couple of years ago.

Closed loop wont drain the tank. Its Closed. from overflow, straight to pump inlet, then out of pump, back to tank, right?

I imagine you have done pretend power outage to see what would happen.

Yes, however it's not so closed anymore once there is a drain in the overflow. Take a look at this diagram that I quickly mocked up (white box is the pump) If you have a power outage, the whole tank is going to drain to the level of the standpipe (standpipe drains to sump - I didn't continue it in the diagram). The water is going to go through the return at the bottom of the tank, into the overflow, and drain down the standpipe in the overflow box. Meaning in the case of this diagram, almost half of the tank would be drained to the sump. Please correct me if I am wrong, but I think that I've thought it through alright in my head. Mr. Alberta said that this exact thing happened to him so he doesn't run the inlet of the closed loop in the overflow box anymore.

http://i600.photobucket.com/albums/t...g?t=1237928761

If what you have drawn is correct, then as the power goes out the overflow would fall to the level of the standpipe going to the sump, the water in the tank would force water back through the pump and into the overflow which would go to the sump.

you are correct, the tank will drain to stand pipe level.

Ohhhhh oh ho !!! Tricky, very tricky!! It took me a while to see it, but yes now I see it. The outlet has to be higher than the standpipe if you don't want that to happen.

My tank is two sides viewable as well, with the overflows on both ends.

My CL intake is midway up the side of one of my OF chambers, plumbed straight through to my CL pump (does not draw from the OF chmber). As you're trying to avoid, is covered with LR but seems to work.

Or I guess a check valve.. But I myself don't like having to rely on a check valve to prevent a flood.