Plumbing sizing for single return pump for two tanks

[wsoldier]

I originally posted in DIY, and I'm now trying to figure out plumbing sizing coming from a single return pump. I was going to T off from my return pump (COR-15) to fit 3/4" line to my display and 1/2" to my frag tank.

Is there any negligible difference if I T off with a 3/4" connector vs going 1" out of my return and reducing both connections? Also, should I have a gate valve to control flow to my display? I'm planning a gate valve on the frag tank drain to control the flow for that. Thanks.

 

[C_AWOL]

Are the holes already drilled for the frag tank? If not I would match the entire plumbing to reduce head pressure which the cor isnt good at handling.
If it's already 1/2" then i would use 3/4 as far of a distance as possible and then reduce as needed towards the end to reduce the length of that back pressure/friction

 

[C_AWOL]

Forgot to mention that if aesthetics isn't an issue then flexible tubing going almost the entire length to a barbed reducer will likely be a lot less head pressure compared to the illustrated 90s and you can use a cheaper 1/2" gate or ball valve and the end as well

 

[oceancowboy]

If you have the ability....make it all 1 inch. I had a 400 gallon that we went to 3/4 inch for the last few feet....really did affect the flow.

 

[NowGlazeIT]

I originally posted in DIY, and I'm now trying to figure out plumbing sizing coming from a single return pump. I was going to T off from my return pump (COR-15) to fit 3/4" line to my display and 1/2" to my frag tank.

Is there any negligible difference if I T off with a 3/4" connector vs going 1" out of my return and reducing both connections?

It make a very small difference because some fittings act as
A choke point. It depends on how much flow you need.

 

[wsoldier]

Forgot to mention that if aesthetics isn't an issue then flexible tubing going almost the entire length to a barbed reducer will likely be a lot less head pressure compared to the illustrated 90s and you can use a cheaper 1/2" gate or ball valve and the end as well

Holes aren't drilled yet (but will be soon!) and aesthetics is a consideration, but I could probably hide the lines if it was flexible tube. I was just thinking I would need a rigid structure in the sump to make things a little cleaner and easier to direct, especially for the drain lines, but maybe that's not true or I should just use pvc for the drains only. I'd have to find some examples to see what it looks like.

Do you think the head pressure is really going to be a factor for a small frag tank 6 feet away? Thanks.

 

[oceancowboy]

It all depends on the pump.....look at the head and flow.....you can find some good online ways to estimate head loss and then look at the pump curves for flow of that specific pump.

 

[wsoldier]

If you have the ability....make it all 1 inch. I had a 400 gallon that we went to 3/4 inch for the last few feet....really did affect the flow.

Unfortunately I can't make it 1" (see my linked DIY thread). I'm only running a 73G display and <20G frag tank.

 

[DCR]

I deal with fluid hydraulics as a profession. You should be able to get about 300 gph through a 3/4" and 150 gph though the 1/2" piping with a COR 15 and a reasonable length of piping. The display would benefit from 1" but should be OK with 3/4". The 20 gal frag should be fine with 1/2"

 

[wsoldier]

I deal with fluid hydraulics as a profession. You should be able to get about 300 gph through a 3/4" and 150 gph though the 1/2" piping with a COR 15 and a reasonable length of piping. The display would benefit from 1" but should be OK with 3/4". The 20 gal frag should be fine with 1/2"

Thanks for those figures! As the others have mentioned, do you also recommend trying to go 3/4" most of the way for the frag tank return up to the bulkhead? I always thought they should not be the same (as the drains), perhaps incorrectly.

I don't mind running a powerhead in the frag tank but if I can get away with not having one that would be ideal.

 

[DCR]

I would use the largest diameter pipe you can and reduce at the tank. If nothing else it will allow you to run your pump at lower speed. If you can run 1" in the common tee section before the split that will help a lot - and then reduce each branch right after the tee. If limited to 3/4", make it as short as possible. I would even put the tee right on the pump discharge threads like you were showing in your sketch. I think you will still want a small powerhead in the frag tank.