Closed loop system

[hayes112]

Hi,

This is just a genaral question. I am going to set up a closed loop system on my 75 gal FOWLR tank becuase I dont want to have to put power heads in it. I was wondering what is the correct way to calacluate head pressure i.e. taking into account the T's and elbows and such. And I read somewhere that it is better to use 1/2 inch PVC or the 3/4 for a closed loop like this, is this correct.

Thanks, Hayes

[ohioreef]

I would think that you'd want the 3/4". It will allow more flow with less resistance. If I remember right, on a closed loop system you essentially have 0 head pressure.

[scott wilson]

The larger the diameter PVC the less friction loose there is.  How much flow are you trying to get?  What pump are you going to use?  How many outlets are you going to have?

Every system has head pressure. You have static head (how high the pump has to push)
You have friction loose if the diameter of plumbing and friction loose for each fitting you are using in your plumbing schematic.

[hayes112]

I just want enough flow for a good current so there are as few dead spots as possible. I am planning on using an Ocean Runner 6500 for the pump to run this . I wanted to know the break down of how to plan out how many outlets I can have or need. For some reason I thought this pump used 3/4 " pvc but it uses 1 inch so I guess thats what I will go with. The pump is rated for about 1700 gph at 0 head.

[scott wilson]

Reef central has calculators for some pumps you can enter the pump.  The diameter of the plumbing the vertical lift the number of 90 t's , ball valves, unions and out lets and it will calculate the head loose and flow.  But your pump is not on the list at 2 meters of total head loose the flow is down to 3500 liters per hour.

[hayes112]

Hey scott thanks for the info. Do you by chance have the link for the calculator that you mentioned?

[Simpte]

If you have an overflow with an unknown gph, is there a way to determine the flow?  I wasnt sure if the flow was determined by the diameter of tubing used for it or not.

[slandis3]

Im not sure how long youhave had your Ocean Runner 6500  but, I have one and I think its useless. For as big as it is, it should push more water. I had it for about 3 months and we had a power outage, when the power came back on the impeller broke. took forever to get a new one. Just my 2 cents.

[hayes112]

I am just setting things up so I havent had a chance to test it for a prolonged period but i hope i have luck with it

[scott wilson]

Just go to reef central and look at the left column there is the head loose calculator there

[scott wilson]

If you have an overflow with an unknown gph, is there a way to determine the flow?  I wasnt sure if the flow was determined by the diameter of tubing used for it or not.

Closed loops do not use overflow boxes.  The intake is under water and depending on the setup has to be primed when you first star it up.

[slandis3]

on my 120 im useing a iwaki 40 with 3/4" pipe. two outputs. I dont want a lot of flow just being able to get rid of my power heads in the main tank.  I set it up so i can go and add more outs later and reduce them to 1/2" if needed. Ill give it a try if it dosent seem to be enough i can disconnect the iwaki and get a larger pump.

[hayes112]

on my 120 im useing a iwaki 40 with 3/4" pipe. two outputs. I dont want a lot of flow just being able to get rid of my power heads in the main tank.  I set it up so i can go and add more outs later and reduce them to 1/2" if needed. Ill give it a try if it dosent seem to be enough i can disconnect the iwaki and get a larger pump.

Quick question salndis3, when you did use the ocena runner did you use it for a closed loop? Also did you run using 1" pipe or did you reduce down to 3/4"

[slandis3]

I used it on a protein skimmer using 1" pipe. I never tried to drop it down to 3/4".