Adding multiple 3/4" returns to increase flow rate

D3DPrintedThingz · Apr 19, 2023

I have moved from a 1" PVC to two 3/4" loc line returns with the random flow nozzles. my return rate seems to have diminished. either the pump is getting dirty or I restricted my flow. a lot of water was coming out of that 1" PVC line, and these nozzles really aren't matching up. My salinity even got a little wonky from the extra evaporation caused from the weaker return rate.

I have the option to print 3/4" y fittings and as many return lines off of those y fittings as possible. I also have a 1" PVC adapter that looks like a mine from minesweeper, and could put 5 3/4" lines on that and it would look like a freaking monster. just looking to get back the efficient rate of flow through the sump and enjoy a little more beneficial flow from my return line. all help is appreciated, thank you

edd59 · Apr 19, 2023

you increased flow with 2 3/4 fittings but dropped pressure in doing so. so it looks diminished

D3DPrintedThingz · Apr 20, 2023

edd59 said:
you increased flow with 2 3/4 fittings but dropped pressure in doing so. so it looks diminished

Do you mean the flow didn’t slow down?

doubleshot00 · Apr 20, 2023

ilikefish69 said:
Do you mean the flow didn’t slow down?

No it would increase. You put those random flow generators on there so its more random. What did you have on there before?

D3DPrintedThingz · Apr 20, 2023

doubleshot00 said:
No it would increase. You put those random flow generators on there so its more random. What did you have on there before?

I had a single 1” PVC , it ran much more gph thru it than the two RFG I have hooked up now.

doubleshot00 · Apr 20, 2023

ilikefish69 said:
I had a single 1” PVC , it ran much more gph thru it than the two RFG I have hooked up now.

I dont understand when you say "1" PVC". Like you had no nozzles or loc line at all? Makes no sense. Sorry

doubleshot00 · Apr 20, 2023

ilikefish69 said:
I had a single 1” PVC , it ran much more gph thru it than the two RFG I have hooked up now.

Is this the orange loc line in your build thread. Just looked through it?

And you switched to a Y locline to 3/4" loc lines with randoms?

D3DPrintedThingz · Apr 20, 2023

doubleshot00 said:
I dont understand when you say "1" PVC". Like you had no nozzles or loc line at all? Makes no sense. Sorry

Yes I’m sorry, it was ugly. The return pump had a 1” PVC slip Union, and that ran all the way up back into the tank. I wanted more

random flow instead of that surge, and put an adapter that accepts 3/4” locline , and the 1” is now two 3/4” Loc line, and flow is not near as much

D3DPrintedThingz · Apr 20, 2023

doubleshot00 said:
Is this the orange loc line in your build thread. Just looked through it?

And you switched to a Y locline to 3/4" loc lines with randoms?

The orange loc line was only a single, I didn’t like it so split it into a Y , but both were considerably less flow

doubleshot00 · Apr 20, 2023

ilikefish69 said:
Yes I’m sorry, it was ugly. The return pump had a 1” PVC slip Union, and that ran all the way up back into the tank. I wanted more random flow instead of that surge, and put an adapter that accepts 3/4” locline , and the 1” is now two 3/4” Loc line, and flow is not near as much

Yeah your pressure should have increased.

This is my exact setup minus the randoms. I dont see a point in them if i have wave makers in my tank.

D3DPrintedThingz · Apr 20, 2023

doubleshot00 said:
Yeah your pressure should have increased.

This is my exact setup minus the randoms. I dont see a point in them if i have wave makers in my tank.

So maybe my return pump is getting dirty? I haven’t ever cleaned it… lol… I don’t have any wave makers, just two gyre . So confused why I lost all my gph, maybe the return sucked up a piece of floss. Wish I would not have hard plumbed the return. Gives me a chance to cut it out and do it better I suppose

doubleshot00 · Apr 20, 2023

ilikefish69 said:
So maybe my return pump is getting dirty? I haven’t ever cleaned it… lol… I don’t have any wave makers, just two gyre . So confused why I lost all my gph, maybe the return sucked up a piece of floss. Wish I would not have hard plumbed the return. Gives me a chance to cut it out and do it better I suppose

Cut it all out and add a barbed fitting then another barb on the pump. Piece of 1” silicone between. What i did.
But yes clean the pump. What pump is it?

D3DPrintedThingz · Apr 20, 2023

doubleshot00 said:
Cut it all out and add a barbed fitting then another barb on the pump. Piece of 1” silicone between. What i did.
But yes clean the pump. What pump is it?

it is jebao the 1500-3000 gph, I ran it at 80% and now have to have it about 92% for it to run the same gph . I can only tell from the last section in the sump, the level will rise or fall depending on the rate of return

edd59 · Apr 20, 2023

ilikefish69 said:
Do you mean the flow didn’t slow down?

flow is the same.

DCR · Apr 20, 2023

The random flow generators add head loss, restrict the flow and will reduce the flow rate for the same pump. What you observed would be expected over an open ended 1" pipe.

D3DPrintedThingz · Apr 20, 2023

DCR said:
The random flow generators add head loss, restrict the flow and will reduce the flow rate for the same pump. What you observed would be expected over an open ended 1" pipe.

If I add more locline lines (with a Y fitting) would that help get flow back ?

DCR · Apr 20, 2023

ilikefish69 said:
If I add more locline lines (with a Y fitting) would that help get flow back ?

Yes, it will help. Loclines are very restrictive because of all the joints and the small diameter, so you may not get back to where you were, but it will certainly help. Whenever you increase the exit velocity with a nozzle to increase the mixing, you are going to reduce the flow rate. I personally don't like to use these types of devices for that reason, but it is a personal choice if you want to increase the mixing in the tank with them or use powerheads to achieve the same thing.

dstockwell · Apr 20, 2023

ilikefish69 said:
I have moved from a 1" PVC to two 3/4" loc line returns with the random flow nozzles. my return rate seems to have diminished.

This makes sense, effectively you went from one 1" to two 3/4" increasing the pipe size more. Do you have a DC pump where you can turn it up to recoup the loss in pressure.

mjw011689 · Apr 20, 2023

I didn’t read through everyone’s replies, but assuming you didn’t change the return pump settings, you did not lose overall flow (gph). You lost pressure. You went from a single 1” opening to 2 3/4 openings… you have the same amount of water flowing through a total of 1.5” of opening instead of through 1”, which is going to reduce the pressure from each opening. I’m not familiar with the random flow generators, are these just the nozzles with the twist in them, or are these the ones that rotate? The ones that have the twist also reduce pressure a little (not noticeable if you have higher pressure to begin with). Not sure about the ones that rotate, but if they’re 3/4 through the entire thing with no reduction, you’ve reduced the overall pressure by splitting it.