Low flow from cannister filters

[Easternlethal]

I have a sun sun 703 and eheim 2217 running on a 50g tank which is about 15x turnover but I'm still not happy with the flow, i guess because i'm using spraybars along the length of the tank.

So I am thinking of removing my biomedia leaving just the filters.

Tank is co2 and heavily planted.

What do people think?

 

[Aqua360]

I have a sun sun 703 and eheim 2217 running on a 50g tank which is about 15x turnover but I'm still not happy with the flow, i guess because i'm using spraybars along the length of the tank.

So I am thinking of removing my biomedia leaving just the filters.

Tank is co2 and heavily planted.

What do people think?

it'll probably block up potentially without the media catching debris I'd imagine, though in fairness I could see people arguing the opposite.

This is on the assumption you have other modes of biomedia for the tank, I wouldn't risk removing it and relying on the tank and plants only.

 

[stu_]

Fish ?

 

[alto]

Specifications on your tank set up will likely get you a better answer

Photos or even just line illustrations are helpful ...
If you look at the Tropica display tanks, many run on the lean side of the 10X turnover "rule" so it's more about good flow rather than lots of flow.

 

[Easternlethal]

Thanks. I'm not sure specifications matter that much because all planted tanks have a lot of surface area for bacteria, and I'm just trying to figure out how much 'extra' is needed, and that would be very difficult to tell just by looking at a tank, I suppose.

I guess it depends on how much ammonia is being released from the tank by fish, dead leaves etc to cycle, so I guess the only way to find out is to keep measuring ammonia and nitrite levels.

I've read from walstad and other members here, especially users of hamburg matten filters that they aren't really necessary and also experts like tom barr that canisters don't really provide great biofiltration anyway (although I've never really understood why).

 

[alto]

also experts like tom barr that canisters don't really provide great biofiltration

hmmm ... thought he got his PhD in quite another field
- certainly without bio-media (not all of which is built equal) a canister filter would be a poor biofilter

I'm not sure specifications matter

Tank size & dimensions, degree of hardscape, density & type of planting, location of inlet/outlet, type of inlet/outlet, inline additions such as heaters/reactors/diffuser etc all substantially impact flow ... you state that you have 15X flow, is this based upon measured flow? and where's it all going that it's insufficient?

 

[Easternlethal]

Because my tank is 90cm long and i am spreading the flow across its entire width using spraybars in order to direct flow down the front glass to reach the co2 hungrier plants in the foreground. With this configuration i have lower flow in certain areas compared to just using a normal nozzle. But a normal nozzle doesn't provide me with the flow at the bottom front portion of my tank that i need (even though other parts of the tank near the top can be quite turbulent).

This is why turnover doesn't equate with flow and they are quite lowly correlated with each other imo.

Of course I could use a wavemaker and there are other solutions.

But the solution I'm wondering about specifically is in removing biofiltration from my canister.

 

[roadmaster]

Any media removed from canister(s) will increase flow.(less resistance)
With that said, I might wonder how often your filter get's serviced.Dirty filter material will restrict flow.
In any event,I might not remove media from both filter's at one go, but rather one at a time over a week or two.
Bio media is kind of redundant in heavily planted tank IMHO.

 

[Easternlethal]

Appreciate your view roadmaster. My filter gets cleaned every month.

So how do you come to this conclusion and how would you manage it? I'm quite curious and keen to try..

 

[xim]

If you have used the filters longer than a year, I think dirty hoses might be the culprit.
Have you tried cleaning them? The result can be dramatic. Biofilm makes the hose wall
less smooth and that will disturb flow pattern and can reduce the flow.

 

[roadmaster]

Appreciate your view roadmaster. My filter gets cleaned every month.

So how do you come to this conclusion and how would you manage it? I'm quite curious and keen to try..

Plant's are best biological filtration for they can/do take up ammonia and nitrates as food/fuel for growth.
Bacteria also colonize's on substrate,plant leaves,glass,rock's,wood, inside wall's/hoses on filter's,and on pad's,sponges, or near anything else placed inside the filter.
If I wanted to increase flow,I would as mentioned remove a foam pad or two depending on how many you have in the filter, or remove bio media from one filter or the other, while leaving the pad's or foam alone till next filter maint.
Personally think the filter's you mention (plural) are plenty of flow for 50 gal .

 

[dw1305]

Hi all,

I think dirty hoses might be the culprit. Have you tried cleaning them? The result can be dramatic. Biofilm makes the hose wall less smooth and that will disturb flow pattern and can reduce the flow.

Usually dirty hoses for me as well.

Because I have my filters next to the tanks if I have impeded flow I tend to cavitation and the filter becomes noisy with trapped air. I clean the intake pre-filter weekly I would think I clean the hoses 3 or 4 times more regularly than I clean the canister.

Are your filters a long way below the tank? If you have a large head height it greatly reduces filter flow.

cheers Darrel