How big is too big for a return pump?

[ryleary]

I am planning on putting my sump in my basement below my display tank (48gal). It would be about an 8ft vertical run from the sump to the tank.

That being said my parents have a 4800gph 18ft head 1.5' output inline pump that was slightly used in a freshwater pond. I know this is crazy big for my sized tank and the run, my question is, is it useable? Could i dial it down with a ballvalve on the after it exits the pump? Or am i just asking for problems.

link to pump http://www.dannermfg.com/store/products/danner/pid-02670.aspx

 

[KorD]

here is the thing to remember, you can idle the pump down by blocking some of the flow with a ball valve, but remember if you block too much of the flow you have a chance of burning up the pump.. another way is to double flow the line to reduce the flow to the tank.. come up with the pipe/line, and make a second split in it. One flow goes to the tank and the other returns to the sump.. you can control how much flows to the sump and that gives you less or more pressure to the tank.... does any of that make sense???

 

[phillrodrigo]

At that height you will have 2300 gph. That's alot. I think with the amount of power they draw it may just be worth buying a new pump. You can do what KorD said also

 

[ryleary]

Yes that all makes sense, thank you. The double flow idea sounds good. I guess Id just be wasting wattage, but its a $250 pump that I dont have to buy. How hard is it to find the balance between the gravity overflow drain and the return pressure?

 

[ryleary]

Whats an ideal GPH for a 48 gal tank?

 

[phillrodrigo]

Like 400 to the tank. So at that height maybe a mag 12 . That's like a mag 48 same company just a different model

 

[KorD]

Yes that all makes sense, thank you. The double flow idea sounds good. I guess Id just be wasting wattage, but its a $250 pump that I dont have to buy. How hard is it to find the balance between the gravity overflow drain and the return pressure?

Should not be that hard... just open the return all the way and then back it off until you are satisfied when the flow into your tank.

 

[TJ's Reef]

[h=2]How big is too big for a return pump?[/h]
If you watch 'Gold Rush' the one Parker stepped up to for his Wash Plant a few episodes ago....... 5000 gallons a minute !!!

I run approx 1050 gph +- now through a 75g Sump/Fuge on my 125g DT and wish that I had nearly double that. I'm a strong proponent of High-flow Sumps though....


Cheers, Todd

 

[Windy]

I have 2 Iwaki MD-100RLT external pumps. I have one as a spare. They will do what you need and more. I run several other tanks as well as a 135, my skimmer and my algae scrubber off of it. By the way, it draws two amps.

Iwaki MD-100RLT (Japanese Motor) 2136 GPH - Bulk Reef Supply#

 

[Reefing Madness]

You don't want the pump returning water faster than your overflows can dump it back into the sump.
If your sump return is to slow, you will need to add a powerhead in there anyway to keep the really nasty top algae from growing.
How does a sump work? | Melev's Reef

 

[Zacco]

here is the thing to remember, you can idle the pump down by blocking some of the flow with a ball valve, but remember if you block too much of the flow you have a chance of burning up the pump.. another way is to double flow the line to reduce the flow to the tank.. come up with the pipe/line, and make a second split in it. One flow goes to the tank and the other returns to the sump.. you can control how much flows to the sump and that gives you less or more pressure to the tank.... does any of that make sense???

Restricting the output flow of a centrifugal pump does not hurt it one bit, unless you cut off the flow entirely. When you restrict the output the motor's load goes down. The motor speeds up because it isn't working as hard. The energy consumption goes down too. If you bypass then you continue to consume unneeded power and add more heat to the water. It is a common misconception that it hurts the motor to restrict the output flow. Think about it. Head height is restriction against the motor. All you are doing by throttling back the flow with a valve is making the pump "think" it is delivering to a higher elevation. (this is all fine as long as you are working within the pumps range as specified by the manufacturer.)

 

[Zacco]

Here are some head loss charts.

 

[AZDesertRat]

The amount of heat a pump that size will add to a 48 gallon tank of water will be tremendous. I recommend about 5 times your display volume for the return pump after headloss and make up any remaining turnover with much more efficient powerheads thtonly draw a couple of watts and produce little heat.

Zacco is correct in post #11 , restricting the discharge versus returning the flow to the sump is a much better alternative. It actually draws less power since the pump is not working as hard, produces less heat and is easier on the pump than having it work to produce al that water only to waste it back to the sump. It can be researched in Bernouli's Theory and The Laws of Affinity or you can simply put a Kill A Watt meter on the pump and try it both ways. I recommend all reefers have a Kill A Watt meter to monitor their power usage, pump efficiencies and lighting power requirements. Neat little inexpensive tools that can actually pay for themselves.

 

[Zacco]

48 gallon display tank x a turn over rate of 5 times per hour= 240 gallons per hour. You have 8 foot of head plus compensation for all the bends in your return pipe. By looking at the Mag Drive Chart above, you would be looking at a Mag Drive 9.5 . A rule of thumb is to double or tripple your GPH turn over rate when looking for a pump to compensate for head loss. It would be cheaper for you to buy a new pump than to pay the electric bill on a 4800gph pond pump. ( you might wanna start looking for a second job to pay that electric bill)

 

[ryleary]

Well that does it, guess I'm getting a new pump. Thanks for all the advice guys.

 

[Zacco]

Do your homework on pumps. May I advise you to steer away from Mag Drive's. They consume more energy and run hot. ( I was only using the mag drive chart above for reference ) I just bought an Ehiem 1260 for my new build.

 

[ryleary]

i cant find an ehiem that has over 10' head

 

[Zacco]

Eheim 1260= 635GPH with a Delivery Head of 12'1" Eheim 1262= 900 GPH with a delivery head of 11'6".

 

[Zacco]

Here's the Ehiem head loss chart.

 

[ryleary]

I ended up going with the Mag 12 because my sump will be in my basement so i dont have to worry about noise and heat will be a good thing, little colder down there. Plus it was about $50 cheaper and Im trying to keep some sort of a budget.