Sizing a return pump

[aravindk]

I am planning a diy sump in my basement for my first floor display tank.
I need help in sizing the pump. My tank is 72 gallons oceanic bowfront reef ready with 1" overflow and 3/4" return.

My current sump is located under the tank. I use a Rio 2100 pump rated
at 692 gph at 0 ft and 375 gph at 4 feet (which is the current height from the sump to the display tank).

Assuming I have to maintain the same 375 gallons per hour water pressure when pumped from basement, I used the Head loss calculator in Reefcentral to caculate the total head loss based on loss of pressure and based it on Little Giant 4-MDQ-SC pump (in-line pump). For 34 feet
horizontal length and 11 feet vertical length with 3 90 degree turns and 1 45 degree turn, I am getting a 462 GPH for this pump. I can add a ball valve to control the return water flow into the tank to reduce the
pressure if necessary.

Is this how I should size the pump? Does anyone know any other method to calculate the head loss? What other factors should
I keep in mind while calculating the head loss?

I appreciate your help.

Thanks

 

[dskidmore]

Sounds like you were pretty through. Any fitting in the line can cause some head loss, are there any fittings not counted in the reefcentral calcuator? If you're upping the volume of the sump while you're at it, I wouldn't sweat a higher return rate, unless your overflow isn't rated for it.

 

[aravindk]

My overflow is untweakable at this time. I see some peole have used a dremel to cut few slots to make it wider. I am not planning to do this since I want to keep it simple especially since this is my first aquarium related diy and first plumbing diy :-(

I forgot to include a union in this calculation. But anyway, I am planning to assemble the plumbing parts before I start shopping for a pump. This way I will have all pieces in the puzzle which should give me a fairly good idea. I hope.

Also is it a good idea to invest in a higher capacity pump so that I can use the additional pressue in future if I decide to add something else (after the return pump). e.g. I am pondering Calfo's technique in future as mentioned in:

http://www.advancedaquarist.com/issues/sept2003/short.htm

Thanks for your comments!

 

[dskidmore]

The manifold looks like a good idea.

Keep in mind that a valve after the pump will increase pressure and wear in the pump.

 

[Tex]

The union will make little if any difference because it doesn't induce any turbulence in the column. Bear in mind that there are short turn and long turn or short radius and long radius 45° and 90° PVC fittings. In your application the long turns would be far better. You've got a sizeable head to overcome!

 

[aravindk]

Tex: The long run pvc fittings, is this something I can ask someone in Home Depot?

dskidmore: That adding a valve will increase the wear on the pump, although sounds quite logical, didnt think of it before. Thank you.

Actually this exchange prompted me ask another but related question. I am posting that as a seperate thread.