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r0bin
04/18/2006, 09:17 PM
Can someone help me with instructions for a closed loop. I know zip about plumbing. What size pump would I need for a 75 gal tank. Also what holds the PVC together, what do you seal it with? If anyone has detailed instructions please help. I have already seen the instructions on melvereef.com, but I do not want to include a wavemaker. He doesnt detail anought how to seal the pipes. Also he says you need acrylic tape? I don't know what that is. This would have to be a hang on the tank plan, as my tank is not drilled. I really need to get some flow in the bottom of my tank.

goda
04/18/2006, 09:41 PM
go to home depot and ask about connecting the pipes an they will show you how ( seeing is better hten reading)
but things to include would be seveal unions and ball vaulve.


to pput the pipes together . cut the pipe. clean with cleaner. apply glue and twist the parts together .

( reason i said to ask homedepot is if it leaks due to not telling you how to do it properly they usualy are forced to accept return :) )

mg426
04/18/2006, 10:18 PM
Try www.melevsreef.com has a great design for a closed loop . even has a parts list to show you what to get.

bertoni
04/19/2006, 12:40 AM
Teflon tape is used to seal threaded junctions. I've never heard of acrylic tape. Most hardware stores have all you need to do PVC plumbing work. The DIY forum is a good resource for this type of issue.

r0bin
04/19/2006, 05:39 AM
Yea I tried the DIY forum but never can use the search. Do you have to cut the PVC? I dont have anything to cut that sort of thing with? Also where do you put the tape and what type of glue is aquarium safe?

eckrynock
04/19/2006, 05:49 AM
????????????????

For a closed loop system on a 75, you would want anywhere from 8 to 12 outlets (for a more random flow). You would want 250 to 350 gph from each outlet. Use the headloss calc on this site (left side of home page) to figure out what gph pump you would need to accomplish this. I'm thinking a large Iwaki or Sequence. You only tape threaded PVC. PVC glue is aquarium safe. Get all the parts you need, dry fit them together to make sure everything fits right. Glue it all together, wait a day and fire it up.

eckrynock
04/19/2006, 05:50 AM
http://www.wetwebmedia.com/pbh2oret.htm

r0bin
04/19/2006, 09:24 AM
Also, another question. The returns on the closed loops are all at the top. I nedd flow in the bottom of the tank?

MCary
04/19/2006, 09:41 AM
First you need to understand what a closed loop is and why its used. A closed loop takes water from below the water line and returns it below the water line. So unless you have a self priming pump, you cannot have a closed loop without drilling your tank.

The reason why closed loops are used is for maximum efficiency of the pump. Since the force of gravity pushing the water into the pump equals the force of gravity needed to push the water back up into the tank, there is no head loss. For this reason you don't need a pressure rated pump and a pump rated at say 1200 gph will return close to 1200 gph minus friction loss due to pipe walls and elbows.

Don't confuse a closed loop with the water flowing through a sump. Its not the same.

Mike

bertoni
04/19/2006, 12:37 PM
For a 75g, I suspect 2-3 outlets would be okay, depending on the total flow that you want. I would put them near the top of the tank to limit disasters if a leak should occur.

I use PVC from the hardware store, and the standard two-part plumbing glue for water supply. You can also get a saw for PVC. The tape is used for parts that screw together, should you choose to buy any. Most parts can be found with "slip" joints that just require a light (very light) sanding and gluing.

_K_E_P_
04/20/2006, 12:35 AM
I'm in a similar sized boat!
Want sized piping would be recommended? 1"?
I'm not sure whether two go for two seperate pumps and loops or one big pump and dividing outputs.

pumpdogs
04/20/2006, 03:43 AM
If your tank is not drilled you could go over the the top and use a spraybar.

bertoni
04/20/2006, 04:18 PM
Each pump will have a recommended output pipe size, and the inputs will need to support the same flow rate, so the same total cross section at a minimum. The drain size calculator on the RC home page might be useful, too.

Gooli
04/20/2006, 04:22 PM
Respectfully, The whole thing about the self-priming pump is not really true (if i understand your comment correctly)...i just finished setting up a closed loop with a eheim 1262 and i fed some water into the tube going to the pump before putting the intake in thet tank. water was pumped in a few times by pluggin and unplugging the pump and it's up and running flawlessly


<a href=showthread.php?s=&postid=7206048#post7206048 target=_blank>Originally posted</a> by MCary
First you need to understand what a closed loop is and why its used. A closed loop takes water from below the water line and returns it below the water line. So unless you have a self priming pump, you cannot have a closed loop without drilling your tank.

The reason why closed loops are used is for maximum efficiency of the pump. Since the force of gravity pushing the water into the pump equals the force of gravity needed to push the water back up into the tank, there is no head loss. For this reason you don't need a pressure rated pump and a pump rated at say 1200 gph will return close to 1200 gph minus friction loss due to pipe walls and elbows.

Don't confuse a closed loop with the water flowing through a sump. Its not the same.

Mike

eckrynock
04/21/2006, 05:06 AM
Golan's right. I have my plumbing running up over the tank. I placed a union just over the back edge of the tank. I pour water down the pvc and then close up this union. I run an Iwaki with no problems.

MCary
04/21/2006, 10:36 AM
You are correct. If you prime the pump manually you can go over the back. My bad. And it should hold enough water in the lines to reprime the pump should the power go out.

eckrynock
04/21/2006, 11:19 AM
That is correct.

eckrynock
04/21/2006, 11:20 AM
I turn mine off everyday to feed.

Gooli
04/21/2006, 01:01 PM
Howard Johnson is right!

(let's see how many people get this joke)