# Multiple Canister Filters and Powerheads



## JGNC (May 15, 2014)

Hello all, I'm having troubles removing dead spots from my tank. It's a 75 gallon Malawi tank with a Rena XP2, XP3 and an Aqueon 950 GPH power head. I currently have both intake tubes on the back right corner and spray bar and nozzle on the left rear. I've played with positioning them along with the power head but I still have areas where waste accumulates.

Does anyone have any pics of a similar setup that works? Should I try an intake/output in the right rear corner with the output facing forward then intake/output on the left rear with the output facing the right? Then have the power head to add to the circular motion. Lastly, I only have one output nozzle and one spray bar, does it matter which I put on the larger filter? The way my tank is setup makes it a pain to move hoses around. Any advice will be greatly appreciated.

Thanks, 
Jesse


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## Mcdaphnia (Dec 16, 2003)

There will always be spots where detritus accumulates if you use laminar flow. The filters, powerheads, spraybars, etc. all produce laminar flow except when they are turned on or off. When they start up, the flow is irregular (turbulent) and then it settles down and smooths out to an even flow (laminar). Reef aquarium keepers can't afford to have a spot where detritus accumulates on a coral or anenome. So they have an electronic device that randomly turns on and off each current making device in the tank so that the flow pattern is constantly changing. Here are some examples of the crazy things that can be done to nearly eliminate any accumulation of detritus.

All it takes is lots of time and lots of money. Or in a freshwater cichlid tank you have the option of siphoning out detritus from those same spots it accumulates, once or twice a week and then replace the water you removed with new.

http://saltycritter.com/pumps/maxspect/ ... erator.htm

http://www.hydor.com/eng/


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## The Cichlid Guy (Oct 18, 2014)

I run my canister intakes in opposite (back) corners, with the outputs pointed towards the center of the tank. So far I haven't noticed any dead spots, and I actually use my powerhead (which is more of a circulation fan) pointed at the surface. I would probably use the spray bar on your more powerful canister, and the directional jet on the other.

In addition to Mcdaphnia's suggestions, I will say that you could run your powerhead(s) on simple household timers, which cost $2-5. You can "program" most of these down to 15 or 30 minute intervals, so you could have your powerhead turn on for a few minutes every hour, or a couple of hours every day, or any combination between.


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## JGNC (May 15, 2014)

Thanks, guys! I have a simple digital timer that I can have the power head go on/off with the lights. Will this work?


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## Mcdaphnia (Dec 16, 2003)

JGNC said:


> Thanks, guys! I have a simple digital timer that I can have the power head go on/off with the lights. Will this work?


Check with the manufacturer of your powerhead. It likely will work but the hard on and off of a light timer could cause excess wear on the motor. I have four of the propeller type powerheads in four different cichlid aquariums. They are all controlled by one wavemaker.


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## Ryan_R (Aug 20, 2014)

Seems like a lot of flow for a 75 gallon tank.... I don't think I have much horsepower on my 125's. That said, the aspect ratio of the tank made my 75 gallon tanks harder to get good flow in than my 125's. I actually have my XP3's in the 125's plumbed into some Magnum 350 pick-up tubes with a 90 degree elbow. This spits water out like 10" under the surface. The XP4's are at surface level pointing "upstream" as the water moves from right to left when facing the tank. Real good for moving water as a unit. With sand, I don't get too much detritus... but there's always a little.

-Ryan


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## JGNC (May 15, 2014)

I ended up setting the power head to only come on for a little while everyday. Just long enough to blow all the **** from the rock piles in to the water column so the filters can deal with it. My tank hasn't been this clean in a while. Thanks for the help!


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