# 90 gallon cichlid tank filtration



## What8585 (Mar 13, 2017)

I have a 90 gallon cichlid tank with 2 fx6 canister filters 
At first had only one but the bio load was too much so bought 2nd fx6 but still see lots of poop floating around 
Water changes are done every week and canisters are cleaned every month 
Why am I not getting crystals clear water and why don't the fx6'S suck all the poop up 
Am I doing anything wrong 
Stock:
25 cichlid 2-4"
1 jack Dempsey 3"
1 10" bottom feeder


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## DJRansome (Oct 29, 2005)

Sounds like too many fish. 10" bottom feeder??? Filters should not suck up ALL debris, just a lot of it. Vacuum weekly to get the rest. It should not fly around the tank...it should lie on the substrate.

Clear water can be a different problem...unless you know the particulates are all feces. What is your total GPH? Maybe you have too much and created a whirlpool?


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## Trademark (Dec 31, 2016)

An FX6 is rated for a 400 gallon tank and your running two in a 90?


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## gillmanjr (Jan 27, 2017)

Trademark said:


> An FX6 is rated for a 400 gallon tank and your running two in a 90?


You can't just go by the manufacturer's rating for canister filters. Particularly with a cichlid tank.  You need to use the flow rate.

I wouldn't think it is too much flow in the tank. The FX6 is rated for about 600 GPH so two of them is certainly a lot of flow for a 90 gallon tank but I wouldn't say its crazy. I have a 50 gallon tank with sump setup and my return pump is rated for 780 GPH, with the head loss and some diverted flow through a reactor I probably move around 400 GPH through my display tank plus I have a 400 GPH wave maker for surface agitation as well. Thats at least 800 GPH of water movement in my 50 gallon and it works really well.

My suggestion would be to position your outlet nozzles better. Even a slight adjustment can make a big difference. I did it a few days ago in my tank because I had a "dead" spot that was accumulating a lot of poop and the adjustment I made fixed it, now I don't see anything sitting on the bottom of my tank, anywhere. It stays so clean that I don't even have to vacuum. I do it occasionally while changing water but there isn't much to vacuum up.


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## DJRansome (Oct 29, 2005)

I would not exceed 10X gallons per hour.


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## gillmanjr (Jan 27, 2017)

DJRansome said:


> I would not exceed 10X gallons per hour.


Why? Its not a problem for the fish. My fish have plenty of places to sit and relax without having to swim against current. I think it would take well over 20 times changeover to produce enough flow to start negatively affecting the fish.


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## DJRansome (Oct 29, 2005)

In my tank 10X starts blowing the fish around. Maybe your aquascape works differently.

Also there is an argument that you want the water to flow though the media relatively slowly so that there is good oxygen and waste exchange for the beneficial bacteria.

We don't all have to do it the same way...gillmanjr you are the experiment guy and I am the "I'd rather not reinvent the wheel" guy.


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## xgtphalex (Jan 30, 2017)

Am I correct in thinking with a sump that 10x isn't a necessity? I think I'm only pushing 7x.


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## Iggy Newcastle (May 15, 2012)

To the OP-
What are your water tests telling you? Ammonia, nitrite and nitrate?


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## DJRansome (Oct 29, 2005)

I have done 4X and 8X and 10X. All were fine. With the 4X you just get more debris on the substrate to vacuum.


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## oval291 (Mar 20, 2017)

gillmanjr said:


> Trademark said:
> 
> 
> > An FX6 is rated for a 400 gallon tank and your running two in a 90?
> ...


How do you not have poop sitting on the substrate with your sump? I am assuming you have an overflow which pulls water from the top. I am curious as I have a sump as well and poop sits on sand until I vacuum.


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## nodima (Oct 3, 2002)

oval291 said:


> gillmanjr said:
> 
> 
> > Trademark said:
> ...


The filtration type (canister, HOB, sump) is a separate issue from seeing detritus on the sand. Detritus on the sand is a function of circulation in the tank, and can be minimized by experimenting with different placement of filter intakes and outlets. Also the type of outlet used can make a huge difference in the visual appearance of detritus. A single jet has a different effect than does a spraybar, for instance. Experimenting with different types of outlets can be eyeopening in terms of what you see (or don't see) and how frequently vacuuming is needed.

Not all overflows only pull from the top of the water column, most of the tanks which are reef ready pull from the lower/mid water column as well as from the top.


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## oval291 (Mar 20, 2017)

Thanks for your response. Ok my overflow is a coast to cost weir at the side so the water overflows and goes down the drain into my sump so my setup only pulls from the top. Therefore I was seeking to add tweaks to address the detritus on the sand between water changes. I added an AC 110 from another tank to pull water water from mid to lower region. I was wondering if I needed to add a powerhead as well....


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