drilling for closed loop, overflow

[Electrokate]

Hi,
I need advice as am about to drill. Tank is a very used truvu 80 which is 48" by 18" by 20". My current tank is a reef ready AGA 55 which I hate because 1/8 of it's volume is taken by the overflow + the huge powerhead & return lines are ugly. I want a minimal overflow this time, and a closed loop instead of powerhead.

I have some parts from another tank I could use: 2 stafford standpipes with 2.5" bulkheads, spray bar, 2 overflows one of which I cut to fit the new tank, mag 12, scwd, and a Grundfos/rainbow lifeguard/pentair aquaculture/quiet one pump + an assortment of 3/4" and 1" bulkheads.

My idea was to put overflow in center. Drill for a pair of standpipes behind it, 1" cpvc for the main drain and a taller 3/4" pvc pipe as backup in case of blockage. Not going for high flow on the overflow, sump is mainly refugium/algal scrubber and a place to put the skimmer. first pic is cross section view of overflow against back of tank.

The overflow itself drilled at the surface for skimming, and there are a pair of 1" holes near the sand level as well. see below-middle pic. Holes near bottom bad idea? (all screened of course) Overflow goes to top flush with acrylic to keep wrasse out. He likes to go for rides and eat the pods in the sump.

The main drain would have a valve on it to keep the intake below water line hopefully controlling gurgles. Thing is this overflow was on the corner of a 90 which gave it much more area, each corner of the 90 had a stafford overflow and 3/4" pvc return on it. I don't know if mounting it flush with the back would make it too small, but in the corner it is too big. Or I can use one of the giant stafford standpipes if it is mounted in the corner, but this tank is not that big and I don't need high flow through the sump... opinions? Corner or back, small or huge standpipes? The stafford takes a 2 1/4" hole.

3rd pic: I'd add a closed loop for flow. question: is a pair of screened 1" intakes enough for this? I'd use the mag 12 with scwd, and lockline for the pair of returns. was going to put the intakes for the CL in the lower outside corners in back, any reason not to do this? The returns I would center in the back on either side of the overflow. I see some of you are using a lot more intakes but on larger sps tanks with more powerful pumps than a mag 12/scwd put out. I am primarily into easier stuff than acros, I keep softies, zoanthids, gorgonians and the hardier sps like montis, birds nests, cats paws and a smattering of faviids. I want good flow balanced in the tank but don't need screaming surf kind of flow... So question is do I need more intake holes, larger holes, or is this good?

Thanks all, you guys are great!
Kate

 

[Electrokate]

Never mind... I read on wetwebmedia this will fail. Also cleaned off the tank and the brace across the top is milky with fine crazing. I think it's too old to be trustworthy.
Kate

 

[Pentagona]

Take a close look at the crazing and see how deep it is. If it's real surfacy then it should be okay, but if it looks like the crazing is pretty deep in the brace I don't know that I would trust it without replacing it. Probably had a MH bulb mounted directly over the top of it at some point. My only thought on your flow is that even for a softy tank it still isn't much. I run my soft tank at about 20x and it's not a real whippy flow. I get pretty gentle motion from everything. Using volume to create flow and not high pressure will give you that soft movement while still being able to move large volumes of water. This usually means either oversizing your outlets, or running multiple smaller outlets. i.e. on my 240 I'm using a 5800gph pump on my closed loop, but it's being pushed through 18 1/2"-3/4" nozzles so I'm only pushing roughly 250gph through each outlet creating gentle but effective flow without blasting any one area of the tank.

 

[Skimmy]

Just cut the old brace and glue or drill/screw in a new acrylic one.


if you want to have something that is inobtrusive in your aquarium, I would suggest bagging the overflow box in the middle and just do one of these:

then, scince your tank is only 80g, you want the return pump from the sump to push only about 240-320gph @4' of head, this way you will get the most bang for your buck from the skimmer/fuge/media reactors employed in your sump. I would suggest an eheim 1260 w/ valve to control flow.

and then, scince it's only a 4' aquarium for predominantly softies/simple sps, I would really rethink the closed loop deal...

I say get just a single powerhead to provide flow for the whole tank and set it up in a gyre configuration.
like this powerhead: 3000gph of flow, 24 watts power consumtion, $44. bam! flow problem solved.
http://www.premiumaquatics.com/Merc...&Product_Code=CV-202B&Category_Code=Octo+Pump

that will provide the aquarium with almost 40x for flow, an excellent amount for what your trying to do.
I think the combination of this overflow and single powerhead will look much slicker than a big box in the middle of the tank and a bunch of inlets/outlets drilled into the back of your tank. not to mention, you wont have to deal with all that plumbing and potential points for leaking/failure that a closed loop has.