How to control flow of drilled tank and return

Ochi · 07/04/2006, 09:00 AM

Well I have a small problem as I set up my tank.

I have a drilled 37 gallon Oceanic tank, drilled by the manufacturer.

Somebody at the LFS who I regard very highly ordered my tank with two 1.5" holes to match the mag 12 I was going to run as a return through an oceans motions squirt. One 1.5" pipe will drain into the refugium, one into the skimmer compartment. My question is the return from a mag 12 is 3/4", and with head loss and all other factors I'm expecting 1100 or so GPH. I have 3" of draining pipes, I fear that I will have far too much water being sucked down from the tank. I wish I went with 1" pipe, but I was told 1.5" was the way to go.

I assume I can just use ball valves on the drains to control their flow correct?

Another question, for the bulkheads can I just fit PVC inside of it? As there are two threads, one on the inside, one on the outside. A standard 1.5" Female FPT/Soc connector doesn't seem to fit on the outside, ideas?

BreadmanMike · 07/04/2006, 09:21 AM

Maybe I'm misunderstanding this, but your concern is that your drains will take too much water out of the tank?

If that's the case, don't worry... The drains will only take out what your pump puts in. If you have a 600gph coming in the tank from the pump, then that is what will go down your drains. The over sized drains will not affect anything.

AZDesertRat · 07/04/2006, 10:59 AM

It will balance itself out.

Ochi · 07/04/2006, 11:38 AM

It's not a closed loop, they are emptying into two compartments, spilling over into a section with a mag 12 and being fed up through the squirt back into the tank.

However my second question still remains, what kind of connector should I use to match the bulkheads...is just sticking PVC in and bonding it possible?

sjm817 · 07/04/2006, 11:42 AM

Mag12 is an awful big return pump for a 37G even though the 3/4" plumbing will restrict the flow considerably. How big is the sump?

Mr James · 07/04/2006, 12:00 PM

Get a Mag5 for you return and see if that does it. I am actually thinking of running a Mag7 type of pump on my 180g. I want slow flow through the sump and reducing the return pump is the only way to do it. I currently run a turned-down Iwaki40RLXT which does about 1200gph, but I want less.

EDIT: Don't put restrictions on your drain, like ball vavles and such.

07/04/2006, 09:00 AM	#1
Ochi Registered Member Join Date: Mar 2004 Location: CT Posts: 264	How to control flow of drilled tank and return Well I have a small problem as I set up my tank. I have a drilled 37 gallon Oceanic tank, drilled by the manufacturer. Somebody at the LFS who I regard very highly ordered my tank with two 1.5" holes to match the mag 12 I was going to run as a return through an oceans motions squirt. One 1.5" pipe will drain into the refugium, one into the skimmer compartment. My question is the return from a mag 12 is 3/4", and with head loss and all other factors I'm expecting 1100 or so GPH. I have 3" of draining pipes, I fear that I will have far too much water being sucked down from the tank. I wish I went with 1" pipe, but I was told 1.5" was the way to go. I assume I can just use ball valves on the drains to control their flow correct? Another question, for the bulkheads can I just fit PVC inside of it? As there are two threads, one on the inside, one on the outside. A standard 1.5" Female FPT/Soc connector doesn't seem to fit on the outside, ideas?

07/04/2006, 11:42 AM	#5
sjm817 On Yer left! Join Date: Sep 2004 Location: Northern VA Posts: 18,777	Mag12 is an awful big return pump for a 37G even though the 3/4" plumbing will restrict the flow considerably. How big is the sump? __________________ - Scott

07/04/2006, 09:21 AM	#2
BreadmanMike Moved On Join Date: Sep 2005 Location: Illinois Posts: 4,886	Maybe I'm misunderstanding this, but your concern is that your drains will take too much water out of the tank? If that's the case, don't worry... The drains will only take out what your pump puts in. If you have a 600gph coming in the tank from the pump, then that is what will go down your drains. The over sized drains will not affect anything.

07/04/2006, 10:59 AM	#3
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	It will balance itself out.

07/04/2006, 11:38 AM	#4
Ochi Registered Member Join Date: Mar 2004 Location: CT Posts: 264	It's not a closed loop, they are emptying into two compartments, spilling over into a section with a mag 12 and being fed up through the squirt back into the tank. However my second question still remains, what kind of connector should I use to match the bulkheads...is just sticking PVC in and bonding it possible?

07/04/2006, 12:00 PM	#6
Mr James Premium Member Join Date: Dec 2001 Location: Kernersville, NC Posts: 6,192	Get a Mag5 for you return and see if that does it. I am actually thinking of running a Mag7 type of pump on my 180g. I want slow flow through the sump and reducing the return pump is the only way to do it. I currently run a turned-down Iwaki40RLXT which does about 1200gph, but I want less. EDIT: Don't put restrictions on your drain, like ball vavles and such.