Submersible pump in filter chamber?

[Akai-San]

I'm putting together a small temporary test pond. Has anyone tried locating a submersible pump within a chambered filtering system to move water from the pond through the chambers and then back to the pond. I'm looking to string together a couple of DIY filterboxes complete with a matala matting stage, then a kaldnes stage, then pumped back to the pond.

My main question is would a 2400-2900 gph submersible pump be strong enough to suck through the filter boxes and stages biological filtration while still providing enough suction at the bottom drain to get the muck out of the pond?

I am also concerned if the 2000+gph pump will throw out too much water out of the filterboxes (faster than water can be replaced) causing an imbalance in the water levels between the two filter-boxes . I'm guessing that if I have a larger sized pipe input into and through the filter-boxes, I won't have this problem of imbalance. Can anyone help me out here? Appreciate any input and words of wisdom.

Aloha,
Carl

[Russell Peters]

If you are going to put a submersible pump in the filter boxes like you are suggesting, then you would need to use a minimum of 4" pipe starting at the bottom drain. You should have no problem with suction then.

Russ

[gregbickal]

This is more flow than you are looking for, but I am currently using a 17,000gph propeller pump for my 8,000 indoor pond. I have four 4" bottom drains (2 per settling chamber), and two 4" niche style skimmers. So six 4" drains total. Pump pushes water back to the pond via 6" pipe.

This pump can only handle 3" of head pressure, so the plumbing requirements are very strict. Other submersible pumps do not have that problem, so you should be ok.

[bekko]

Hi Carl.

I think this calculator will help.
http://www.efunda.com/formulae/fluid..._tank.cfm#calc

For the "depth of spout" value, enter the maximum acceptable difference in water level between the pond and the first chamber (1"). Then enter the pipe diameter where it says "exit spout diameter" (3"). If the calculated flow is less than the capacity of your pump (in gallons per minute), then you have a small problem. If the chambers are connected to each other by a pipe, then the "draw-down" (water level difference) is cumulative. Example, 1" draw-down from pond to first chamber, another 1" draw-down from first chamber to second chamber, etc.

Whether or not the 2400 gph flow will pull the solids from the bottom of the pond depends on the the current and deposition areas in the pond, whether or not there are air domes, etc. If the 2400 gph is pumped back into the pond parallel to the wall, there will be a somewhat circular flow pattern and the solids will be pushed towards the center. That would be where you want to locate the drain.

Regards,
-steve

[Akai-San]

Steve,

Thanks again for all your help. Is there any reason why I should be concerned if the flow rates were considerably greater. Is it bad to have the water pass through the filter media stages too fast?

Aloha,
Carl

[Russell Peters]

Quote: Originally Posted by Akai-San Steve, Thanks again for all your help. Is there any reason why I should be concerned if the flow rates were considerably greater. Is it bad to have the water pass through the filter media stages too fast? Aloha, Carl

Yes, gravity flow works with gravity and if your flow is too great then the velocity of the water going through the chambers will not allow the solids to settle out nor will it allow the proper contact time for nitrification.

Russ