Closed Loop Question

[TruReef]

Im setting up a 180gal AGA reef ready tank. It will have two mega flow overflows on it. I want to know if I can use one overflow as a drain and return for the sump, and the other as a Closed loop for tank circulation. I know the one going into the sump will be fine but am curious if this can be done to prevent having to drill the back of the glass.....

 

[GOLFREEFER]

That would work ok in my opinion but you would only have one outlet for the closed loop and usually closed loops are used for random flow with lots of entry points. Also in a 180 gallon tank you are better off using the overflows for the filtration equipment to get the most "crud" into the overflow so you can skim it out.

Only using 1 overflow will limit your skimming of the water surface of organics.

 

[TruReef]

I do plan on running the return of the closed loop over the back with multiple input points.

 

[Gold Stripe]

You are MUCH better off drilling a 1.5 inch bulkhead in the center of the back wall to feed your closed loop.

First, you will be limited in the amount you can draw from a built in overflow. Its not a true closed loop because the water has to enter the overflow before it can enter your closed loop so you are restricted to the amount of water that can enter.

Second, you will be giving up a lot of flow available to your sump. Redundancy is key and I assure you that when that turbo snail finds its way into your overflow, you will wish you had the other one functioning as all the water from your sump overflows the top of your tank from your return pump.

Third, as mentioned earlier. The overflows are smaller because there are two of them. If you stop using one for its intended purpose then thats just more skimming ability you are giving up because stuff on that end of the tank will have a much harder time getting to the functioning overflow on the other end.

I promise that you will be soooooooo much happier if you go ahead and drill for the closed loop.

 

[GOLFREEFER]

Gold Stripe, that is a great point, as I understand it Closed loops are efficient because it basically removes the head pressure from the pump because of the closed nature of the loop. It uses gravity from the tank so it is a net result.

If you let it overflow you are adding the head pressure, I think this is correct anyway don't quote me on that.

 

[TruReef]

OK, I guess I will drill. wish me luck .........

 

[GrindingNemo]

I wouldnt drill it yourself if you have never drilled glass before. Glass shops will usually do it for pretty cheap.