Closed Loop Design Thru Tank Bottom

expat701 · 01/05/2009, 04:13 PM

I'm planning to include a closed loop in my new reef tank. It will have PVC returns in the back on the tank as well as at various points around the tank bottom. My plan is to get as good a flow as possible around my rock.

I've seen a lot of closed loop designs on here that include drilling the bottom of the tank. I understand I need to include ball valves for maintence as well as threaded joints to enable the plumbing to be removable...

My question is should I include one way check valves for the bottom returns??? Between the bulkhead and the ball valve?

I'm concerned about the possibility of a mistake or serious leak siphoning the entire tank thru the bottom returns.

If check valves are recommended, which is better - flapper or ball check valves???

Can anyone show me a good closed loop design with bottom returns that includes check valves in the design?

As always thanks in advance for the help and advise!!!

---Wayne

Untamed12 · 01/05/2009, 04:24 PM

My tank has 4 CL outputs in the bottom of the tank...but I don't have check valves on any of them.

When you think about it....in terms of possibly draining the tank, the holes on the bottom are only a few inches lower than some of the holes/pipes on the sides. Unless your CL pulls/push all of the water over the top edge of the tank, a leak anywhere in the CL has the potential to drain the tank to the lowest point of the CL system.

I suppose check valves would reduce the risk of something happening, but I don't know of anyone who has installed them on every intake/output of a CL.

expat701 · 01/05/2009, 04:36 PM

My design will have returns in the back of the tank that are quite high - not much lower than the overflow height (they will push water downwards over the rock).

The CL pump intake will be about 3/4 of the way up the tank.

As such I'm not so worried about the back returns/pump intake siphoning much water (potentially max of only 1/4 of the volume) but the tank bottom returns would siphon the whole tank; hence my thoughts to include the check valves.

Having said all that... if went to the effort of putting check valves on the bottom returns I'd probably go ahead and put them on all the returns and the pump intake (cover all bases).

Smitty750 · 01/05/2009, 05:20 PM

?????? Its a CLOSED LOOP intake and return both attached to a pump, 1 line siphons water from the tank 1 line returns water to the tank. Where is it gonna go? Once the pump turns off the water stops moving and sits in the pipes you ran theres nothing to siphon its a loop! No worries bud your safe with or without the checks, def ballvalves and unions though. Also remember that the more outputs u have on the loop the ones closer to the end will have low pressure the ones in the begining will have higher flow. U should connect both ends of the discharge or return to equalize ur pressures

expat701 · 01/05/2009, 05:31 PM

Smitty, it's conceivable a leak in a join; someone accidently unscrewing the threaded join to the pump (without my knowledge and without first turning off the ball valve); or the seal in the pump failing could break the CL and commence a siphon... One that potentially would drain the whole tank.

I know I'm being overly conservative, but I'm a think of all potential failures and design in contigencies kind of guy...

I guess I should have just gone in with the questions.... is there anything "wrong" with putting a one way check valves on the inlet and outlets of a CL, simply as a precaution?

And

What is the difference between a swing and ball type of check valve???

--Wayne

sober_pollock · 01/05/2009, 05:45 PM

Not really much point in putting check valves in the "inlet" of the closed loop" (The one that pulls water out of the tank).....

Since the water on this line normally flows out of the tank, the check valve would be oriented such that it would allow water to flow out but not in......

Doesn't really protect that way.

expat701 · 01/05/2009, 06:23 PM

Ha ha.... you're right. Scrap putting a check valve on the inlet to the pump, only on the outlets in the back and bottom of the tank.

Jeremy Blaze · 01/05/2009, 06:55 PM

Yes, no need for check valves in a closed loop.

However, ball valves are very important. You will want one on the inlet and outlet of the pump, true union ones would be even better. They will be very useful when its time to take the pump off and clean/ repair it.

As for check valves on the return, I like the foot valve design that is installed on the intake side of the pump.

When it comes to plumbing the tank, and closed loop there are so many ways, and not one is the Right way. It really depends on the particular tank, its planned inhabitants, and overall look or goal of the tank.

Just curious, is this a 220 your setting up?

expat701 · 01/05/2009, 07:27 PM

Thanks for the feedback. The tank is around 120 gallon.

Would there be anything wrong with having check valves plumped after the bulkhead (before the ball valves) on the CL outlets??? Purely as a siphon precaution?

Jeremy Blaze · 01/05/2009, 07:41 PM

There would be nothing wrong with it, just unnessecary.

expat701 · 01/05/2009, 07:47 PM

Jeremy, final question... what did you mean by "I like the foot valve design that is installed on the intake side of the pump"??? I thought you can't put a check valve on the inlet to the pump as it would stop the flow to the pump. If I've got them on all the outlets into the tank, what would having one on the inlet to the pump achieve? What "direction" would it face?

Jeremy Blaze · 01/05/2009, 08:03 PM

The problem with check valves on the return side of the pump, is that if the valve is far from the pump, when it shuts off the water can drain from the pipe between the valve and the pump. THis can cause an air lock that some pumps can not overcome.

THe foot valve will not allow any water to drain from the pump, keeping it primed.

Here is a foot valve,
http://www.aquaticeco.com/subcategor...foot%20valve/0

psteeleb · 01/05/2009, 09:06 PM

Quote:

Originally posted by expat701
Thanks for the feedback. The tank is around 120 gallon.

Would there be anything wrong with having check valves plumped after the bulkhead (before the ball valves) on the CL outlets??? Purely as a siphon precaution?

I would not do it

first off all check valves will go bad it's just a matter of when

salt water tank piping gets a lot of growth inside it and this in itself will make the check valves useless in a few months.

I have a bottom closed loop and have ball valves as close as possible to the bulkheads for shut off - they are there for pump maintenance and precautionary measures

here is an old picture showing a worms eye view of mine (at least most of it)

psteeleb · 01/05/2009, 09:06 PM

dp

01/05/2009, 04:13 PM	#1
expat701 Registered Member Join Date: May 2005 Posts: 42	Closed Loop Design Thru Tank Bottom I'm planning to include a closed loop in my new reef tank. It will have PVC returns in the back on the tank as well as at various points around the tank bottom. My plan is to get as good a flow as possible around my rock. I've seen a lot of closed loop designs on here that include drilling the bottom of the tank. I understand I need to include ball valves for maintence as well as threaded joints to enable the plumbing to be removable... My question is should I include one way check valves for the bottom returns??? Between the bulkhead and the ball valve? I'm concerned about the possibility of a mistake or serious leak siphoning the entire tank thru the bottom returns. If check valves are recommended, which is better - flapper or ball check valves??? Can anyone show me a good closed loop design with bottom returns that includes check valves in the design? As always thanks in advance for the help and advise!!! ---Wayne

01/05/2009, 04:24 PM	#2
Untamed12 Registered Member Join Date: Dec 2005 Location: Canada Posts: 1,578	My tank has 4 CL outputs in the bottom of the tank...but I don't have check valves on any of them. When you think about it....in terms of possibly draining the tank, the holes on the bottom are only a few inches lower than some of the holes/pipes on the sides. Unless your CL pulls/push all of the water over the top edge of the tank, a leak anywhere in the CL has the potential to drain the tank to the lowest point of the CL system. I suppose check valves would reduce the risk of something happening, but I don't know of anyone who has installed them on every intake/output of a CL. __________________ Fishlist: Tangs: Yellow, Vlamingi, Blonde Naso, Unicorn, Atlantic Blue Others: Maroon Clown(s), Foxface, Majestic Angel, Hawkfish and more.. Current Tank Info: 400gal Envision Acrylic reef started 04/07

01/05/2009, 05:20 PM	#4
Smitty750 Registered Member Join Date: Feb 2006 Location: Bethel, Connecticut Posts: 607	?????? Its a CLOSED LOOP intake and return both attached to a pump, 1 line siphons water from the tank 1 line returns water to the tank. Where is it gonna go? Once the pump turns off the water stops moving and sits in the pipes you ran theres nothing to siphon its a loop! No worries bud your safe with or without the checks, def ballvalves and unions though. Also remember that the more outputs u have on the loop the ones closer to the end will have low pressure the ones in the begining will have higher flow. U should connect both ends of the discharge or return to equalize ur pressures __________________ Um, I need money!!! Current Tank Info: 125 AGA Work in progress

01/05/2009, 06:55 PM	#8
Jeremy Blaze Former Reef Addict Join Date: May 2003 Location: New Washington, IN Posts: 5,864	Yes, no need for check valves in a closed loop. However, ball valves are very important. You will want one on the inlet and outlet of the pump, true union ones would be even better. They will be very useful when its time to take the pump off and clean/ repair it. As for check valves on the return, I like the foot valve design that is installed on the intake side of the pump. When it comes to plumbing the tank, and closed loop there are so many ways, and not one is the Right way. It really depends on the particular tank, its planned inhabitants, and overall look or goal of the tank. Just curious, is this a 220 your setting up? __________________ Trust me my friend, the names are not important at all. I've own hundreds of different zoas and palys and don't know the name of a single one. In my opinion, they are a waste of valuable time. Mucho Reef

01/05/2009, 07:41 PM	#10
Jeremy Blaze Former Reef Addict Join Date: May 2003 Location: New Washington, IN Posts: 5,864	There would be nothing wrong with it, just unnessecary. __________________ Trust me my friend, the names are not important at all. I've own hundreds of different zoas and palys and don't know the name of a single one. In my opinion, they are a waste of valuable time. Mucho Reef

01/05/2009, 04:36 PM	#3
expat701 Registered Member Join Date: May 2005 Posts: 42	My design will have returns in the back of the tank that are quite high - not much lower than the overflow height (they will push water downwards over the rock). The CL pump intake will be about 3/4 of the way up the tank. As such I'm not so worried about the back returns/pump intake siphoning much water (potentially max of only 1/4 of the volume) but the tank bottom returns would siphon the whole tank; hence my thoughts to include the check valves. Having said all that... if went to the effort of putting check valves on the bottom returns I'd probably go ahead and put them on all the returns and the pump intake (cover all bases).

01/05/2009, 05:31 PM	#5
expat701 Registered Member Join Date: May 2005 Posts: 42	Smitty, it's conceivable a leak in a join; someone accidently unscrewing the threaded join to the pump (without my knowledge and without first turning off the ball valve); or the seal in the pump failing could break the CL and commence a siphon... One that potentially would drain the whole tank. I know I'm being overly conservative, but I'm a think of all potential failures and design in contigencies kind of guy... I guess I should have just gone in with the questions.... is there anything "wrong" with putting a one way check valves on the inlet and outlets of a CL, simply as a precaution? And What is the difference between a swing and ball type of check valve??? --Wayne

01/05/2009, 05:45 PM	#6
sober_pollock Registered Member Join Date: Sep 2008 Posts: 37	Not really much point in putting check valves in the "inlet" of the closed loop" (The one that pulls water out of the tank)..... Since the water on this line normally flows out of the tank, the check valve would be oriented such that it would allow water to flow out but not in...... Doesn't really protect that way.

01/05/2009, 06:23 PM	#7
expat701 Registered Member Join Date: May 2005 Posts: 42	Ha ha.... you're right. Scrap putting a check valve on the inlet to the pump, only on the outlets in the back and bottom of the tank.

01/05/2009, 07:27 PM	#9
expat701 Registered Member Join Date: May 2005 Posts: 42	Thanks for the feedback. The tank is around 120 gallon. Would there be anything wrong with having check valves plumped after the bulkhead (before the ball valves) on the CL outlets??? Purely as a siphon precaution?

01/05/2009, 07:47 PM	#11
expat701 Registered Member Join Date: May 2005 Posts: 42	Jeremy, final question... what did you mean by "I like the foot valve design that is installed on the intake side of the pump"??? I thought you can't put a check valve on the inlet to the pump as it would stop the flow to the pump. If I've got them on all the outlets into the tank, what would having one on the inlet to the pump achieve? What "direction" would it face?

01/05/2009, 08:03 PM	#12
Jeremy Blaze Former Reef Addict Join Date: May 2003 Location: New Washington, IN Posts: 5,864	The problem with check valves on the return side of the pump, is that if the valve is far from the pump, when it shuts off the water can drain from the pipe between the valve and the pump. THis can cause an air lock that some pumps can not overcome. THe foot valve will not allow any water to drain from the pump, keeping it primed. Here is a foot valve, http://www.aquaticeco.com/subcategor...foot%20valve/0 __________________ Trust me my friend, the names are not important at all. I've own hundreds of different zoas and palys and don't know the name of a single one. In my opinion, they are a waste of valuable time. Mucho Reef

01/05/2009, 09:06 PM	#14
psteeleb Registered Member Join Date: Oct 2005 Location: DFW Texas Posts: 5,249	dp __________________ A smooth sea never made a skillful mariner Current Tank Info: 110g Mixed Reef, LED's & T5's