PVC Flow Rates ?

[pacu mom]

I have searched but can't find a "good" graph, chart or calculator for determining drain flow rates on pvc.

I have two overflow boxes on my 300 that have openings for 2" pvc. I was hoping to get away with only using one of the boxes for the wet dry and utilizing the other for my inline canister and uv setup.

The 2" pvc will flow thru a Durso Standpipe then through no more than (3) 90 degree elbows on its way to the wet/dry filter. Anybody have an idea of a ballpark drain rate for this?

Our tank has the same foot print as your tank. We are only using one overflow box for our wet dry system, and it's been working out just fine. Our wet dry filter (rated up to 400 gallons or 1600gph) is a 28 gallon sump with 12 gallons of bio balls. The wet dry filter has a dual inlet at the top which is fed from the PVC pipe coming from the one overflow box. The pump in the wet dry filter is a CA-6000 (1560 gph).

I'm not sure why you need to know the flow rate. Is it to determine the pump you will need for your wet dry system? The pump does not have to exactly match the flow rate from the overflow box. (Close is good enough) You must have enough water in the wet dry filter to keep it at a certain level. If the pump was pumping out faster than the flow rate from the overflow box, you would have more water in the wet dry to begin with (more water circulating in the system overall). When the electricity is out, the water level always rises in the wet dry filter. The extra water would be water that was in the pipe and the difference between the flow rate of the pump and the overflow box.

 

[Bud8Fan]

I would like to know the flow rate to determine if I can get enough turnover in my wet/dry filter by using only one overflow. I was hoping to get somewhere around 1000 - 1200 gph of flow thru one drain. johnptc's example of 9.8gpm equals 588 gph which is not near what I was hoping for.

Why do I only want to use one? I have two Ocean Clear filters and a UV Sterilizer that I was going to pipe thru the second overflow box.

My goal is to eliminate the need to drill additional holes so that I can have this tank sit as close to the wall as possible by utilizing the overflow boxes.

 

[johnptc]

remember that if the water rises a little the flow down the pipe will increase...... a 2 inch pipe can drain alot of water

I would like to know the flow rate to determine if I can get enough turnover in my wet/dry filter by using only one overflow. I was hoping to get somewhere around 1000 - 1200 gph of flow thru one drain. johnptc's example of 9.8gpm equals 588 gph which is not near what I was hoping for.

Why do I only want to use one? I have two Ocean Clear filters and a UV Sterilizer that I was going to pipe thru the second overflow box.

My goal is to eliminate the need to drill additional holes so that I can have this tank sit as close to the wall as possible by utilizing the overflow boxes.

 

[Bud8Fan]

Exactly why I have been looking for some sort of chart or calculator that I can plug my variables into.

I'm thinking I may just go buy a cheap large plastic trash can and do some experimenting in the driveway with some 2" pipe, elbows and stopwatch.

 

[Dr Joe]

I just had this horrible vision of you like a fountain stuck to the driveway till the spring thaw...

 

[Bud8Fan]

If the weatherman isn't full of crap we are supposed to get away from the freezing temps starting tomorrow and 60's by next week.

 

[Dr Joe]

All right then...You got a chance .

Keep us posted on your findings.

Dr Joe

.

 

[Bud8Fan]

Hopefully this weekend or next. I'll record results and maybe even take some pics of my sure to be weird looking contraption.

 

[Bud8Fan]

Found a cheap 24 gallon rubbermaid and rigged up a test setup last night after work. I drained it with 2" pvc using zero elbows and three elbows. Both times I drained the container in 16 - 17 seconds. The test was not very accurate by myself. Hard to turn the 2" ball valve and start the clock at the same time.

Hopefully Saturday I can get a buddy to help.
I also want to test how fast it takes to drain the top half versus the bottom half to see just how big of an effect the water level above the drain has.

 

[johnptc]

see http://www.grow.arizona.edu/Grow--GrowResources.php?ResourceId=188

nice calculator

Found a cheap 24 gallon rubbermaid and rigged up a test setup last night after work. I drained it with 2" pvc using zero elbows and three elbows. Both times I drained the container in 16 - 17 seconds. The test was not very accurate by myself. Hard to turn the 2" ball valve and start the clock at the same time.

Hopefully Saturday I can get a buddy to help.
I also want to test how fast it takes to drain the top half versus the bottom half to see just how big of an effect the water level above the drain has.