Is my pvc too big?

[ngav3]

So i will be building an overflow for a 75 gallon tank. Im using uarujoeys original design, and i have some 2" pvc lying around that i can make the overflow out of. The return pump from the sump is 1000 gph (it has adjustable flow rate, 1000 is the max.)

Should the 2" pvc work or will it be too big?

Thanks in advance
Nick

 

[Red_Man]

2 inch PVC with gravity as its only motivator can flow 1500gph. Considering your pump is rated for 1000gph you will have to account for head loss which means you may be flowing 700+/- gph back to the tank which is a turn over rate of just over 9 times. Hope you plan to keep fish that like strong flow in the tank. I oversized the plumbing on my 125g and it is very noisy if you are using Joeys' double U design. The water crashes to the bottom of the pipe and echos back out into the room really bad. You may consider down sizing or looking at his updated version of that overflow.

 

[ngav3]

What size pvc should i use? 1 1/2?

 

[Niners4952]

I would go with 1" and if your doing the double u then your pipe in the tank would be 2", I have a 320 gallon with 2 1.25 drains and it drains almost too fast

 

[Red_Man]

Sorry I didn't see your post. Forgot to hit the "watch thread" button.

Diameter of PVC = Gravity fed GPH
1/2" = 90gph
3/4" = 220gph
1" = 375gph
1-1/4" = 580gph
1-1/2" =840gph
2" = 1500gph

Hope this helps you make a decision for what will work best for you. I have 125g with two 1-1/4" King of DIY double U overflows. I am flowing just over 500gph through them and if I turn my pumps up any higher they get really noisy and I get the gurgle sound a bit.

 

[millerkid519]

Sorry I didn't see your post. Forgot to hit the "watch thread" button.

Diameter of PVC = Gravity fed GPH
1/2" = 90gph
3/4" = 220gph
1" = 375gph
1-1/4" = 580gph
1-1/2" =840gph
2" = 1500gph

Hope this helps you make a decision for what will work best for you. I have 125g with two 1-1/4" King of DIY double U overflows. I am flowing just over 500gph through them and if I turn my pumps up any higher they get really noisy and I get the gurgle sound a bit.

Have you tried his updated version of the overflow or is this with the original design

 

[Red_Man]

millerkid519
That's the original design flow rates he gave. The new version he says flows 60% more. I plan to make the switch. Just haven't done it. Got the pieces sitting here glued and painted. Just need to cut the old stuff apart but I'm hesitant cuz the tank is full of fish now.