GPH loss due to headspace and elbows?

[Brandon8521]

How many gph would i lose with a 4ft headspace and 2 90dgr elbows on a 600gph pump?

[J-P]

good question ...

have you tried the pump manufacturer? usually they have a head / GPH ratio. 4ft head with a 600GPH seems kind of small depending on the tank.

[Brandon8521]

Im just trying to get a shopping list together for my 33 gal tank i am going to make one of my 10gal spare tanks a diy sump/ref, aswell as trying out a diy overflow box made out of speciman boxes. I have my old 600gph pond pump and was thinking about useing that as a return pump. Do you think i would need a larger pump? Im going to shoot for around 100 gph.


Also if anyone could suggest a good lifter pump so that i can regain a syphon during a power outage that would be great. (Edit* ok i think i can manage without a lifter pump)
I think im settling for the turbolift 1000 blue skimmer aswell. It will hang on my sump since it will be snug down there.

[Mek0ng]

How many gph would i lose with a 4ft headspace and 2 90dgr elbows on a 600gph pump?

Reef Central's Head Loss Calculator:

http://www.reefcentral.com/index.php/he ... calculator

[Brandon8521]

It wont let me choose a pump?

[Mek0ng]

It wont let me choose a pump?

Hmmm I guess its broken, I havent used it in years...

Either way, what size is your drain? I know a 1" drain is rated at 600gph, and a little less in practice. I would say you are fine with a 600gph pump and going to be well above 100gph, but you are going to have to get a gate/ball valve to turn the pump down. Try the pump you have and then see.

The calc told me back when I set up my 90g that my mag 950gph would be putting out around 600gph at 4.5 feet of vertcal run and 3 90* and 2 45* bends on a 3/4" pipe.

[Brandon8521]

After looking at the pond pump im really sketchy on useing since it has 4 screw heads that would be in contact with the water. I dont think i want to take a chance it rusting or something. But my plan is a pvc overflow so i dont have to deal with the size of a box overflow in such a small tank. Either 1/2 inch or 3/4 and the return will probably be 1/2 inch. My next buy is a skimmer, then some live rock and then i will build the sump/ref. This will be about one buy a month since im working on a limited budget. The reason i want it to run 100-150 gph is because i will transfering all of this over to a 55 around the end of this year. Im thinking about either the maxijet1800 or 1100. But just wanted to get a good estimate on how much flow rate i would be looking at.

[Mek0ng]

After looking at the pond pump im really sketchy on useing since it has 4 screw heads that would be in contact with the water. I dont think i want to take a chance it rusting or something

Many pumps have screws like that, mag pumps for one, used by many people (including me) with no rust potential.

But my plan is a pvc overflow so i dont have to deal with the size of a box overflow in such a small tank. Either 1/2 inch or 3/4 and the return will probably be 1/2 inch. My next buy is a skimmer, then some live rock and then i will build the sump/ref. This will be about one buy a month since im working on a limited budget. The reason i want it to run 100-150 gph is because i will transfering all of this over to a 55 around the end of this year. Im thinking about either the maxijet1800 or 1100. But just wanted to get a good estimate on how much flow rate i would be looking at.

From melvesreef:

To establish flow rates, you have to get a pump that will match how fast the drain will flow. I have a 1" drain on mine, and because there is no volume of pressure over that drain (or bulkhead), my maximum flow rate is 300gph. If the bulkhead were at the base of the tank, and I had gallons of water pressing down due to gravity, it might drain as much as 600 gph. But that is not the case. In the outer box of the weir, there is maybe a pint of water, so it goes more slowly. You want to find a return pump that will match your drainline, but you also have to figure head pressure as well. How far does the pump have to push water back up to the top of the tank to refill it? The submersible pump in the sump under my 29g has to push water straight up 5 feet. So a Mag 5 at 5' pumps 300gph. A perfect match!

Since you are going to DIY your overflow, pick a over-sized drain line, the further you are away from maxing out your drain line's gph, the less noise (gurgling) the drain will make. Since you are going to be upgrading to a larger tank you might want to pick a over-sized pump as well to match the new tank. You can always put a T off the return line back to the sump to bleed off the excess gph from a over-sized pump.

[Brandon8521]

my pond pump has a valve to adjust the flow rate but i have no way of telling what the head pressure is since i cant anything about it online(it comes as a kit.) I think i will try it out since it didnt rust the summer i had it setup (but the saltwater factor makes me nervous.)

Im going with this style overflow but plan on putting some sort of grate where the water flows in at. So maybe 1in pvc will work?
http://www.youtube.com/watch?v=kjSLPVoLIs4

[Nick]

I have heard that despite logic, four 45 degree elbows have less GPH loss than two 90 degree elbows due to fluid friction maths I don't know well enough to dispute.