closed loop intake inside of overflow box ?

[scottjj]

My 215g is bottom drilled with puny 1" drain holes in each corner. I plan to get about 600 gph from each and to get more flow in the tank I am going to add a closed loop with a Mag18 off of a 1.5" intake and 4-5 outlets.

I would live to hide the 1.5" pvc intake pipe INSIDE the vertical overflow, between the standpipe and the return pipe...it fits no problem......My question is will there be enough water in there to feed both the overflow and the closed loop intake ? I'm sure someone has done this before....

[Doug1]

I suspect that it will cause the overflow to drain quickly, and noisily. I would make the intake to the CL seperate than the overflow

[Acrylics]

You'll have 2 issues:
The first is that the overflow may not be able to handle the flow for both.
Second is that because of all the turbulence in the overflow, the CL intake will have a ton of bubbles in it.

You can drill a hole in the side of the overflow, and elbow down from this to the intake hole for the CL. Hope this makes sense. This is much easier to do before the overflow is installed but can be done after as well.

HTH,

James

[wanareef]

I'm with Doug

[scottjj]

after doing some more logical thinking, I agree on both 2 issues; the slots cut in the overflow would surely not allow enough water flow to feed both, then assuming they were enlarged and oversized, then the turbulence in the overflow would indeed put too many bubbles into the CL intake.

I do not want to drill the back of the tank and the idea of cutting a hole in the side of the overflow has possibilities...the tank will be filled this weekend, so I couild make some time to do that..... I suppose a dremel tool would do the job....I'll have to see if there is room for a bulkhead and an elbow to fit in there...

[wanareef]

Why not enlarge the hole for a bigger BH in the bottom, before you fill it up? 1" is awful small for a 218gal tank, sounds like poor design on the tank builder. IMO a mag 18 is too small a pump for a CL on that size tank.

On my 330gal for the CL, I will be using a Sequence 4200, maybe 2 of them. You can never have enough flow.

[scottjj]

I could, but this beast is simply to much of a PITA to move around....would you suggest re-drilling another larger hole in the same spot ? or is there a better / easier way to enlarge an existing hole ?

[wanareef]

I would hassel with it "now" than not doing it and have wished that I did do it. Is the tank glass? Acrylic?

Glass- You can use those diamond burrs that Harbor frieght sells for 5-6$ for 20pcs to make the hole bigger.

Acrylic- You can use the same thing, or use a Fostner type bit (woodworkes) to make it larger. A sanding drum works well here but is a little slow.

Just make sure you have the Bh "in hand" before you make the hole larger. You could just add another Bh to increase the water going out, if you have the room.
Or live with what you have and add a CL for flow. That is where the "flow" or "turn over rate" would come from. Why don't you want to drill the back of the tank for a CL eaiser in the long run. Checkout this post, his design is taken from several others and incorporated into this: http://www.reefcentral.com/forums/sh...hreadid=371622

good luck