CO2 into filter

[Andrew Lindsay]

Is it detrimental to the active bacteria culture in a power filter to direct the CO2 bubble stream into the suction pipe? Thanks

 

[Akmaliano]

Simple answer - no. The CO2 doesn't get locked within the filter forever as the filter moves the water continuously so in theory after short time the amount of dissolved CO2 in the filter will more or less equalise to the amount of CO2 in the aquairum. I've never had problems with mine.

 

[ian_m]

Except that CO2 dissolves in rubber and can make the rubber filters seals either melt or go hard (depending on rubber type) after a while. This has been seen on this forum before. Also many filters can suffer from "burping" where they periodically expel trapped CO2. Your "mileage" and experience my differ of course.

 

[Zeus.]

As replied pros and cons OFC.
Also the impeller of the pump can help reduce the size of the CO2 bubbles with some impellers available with holes in them to crease turbulence around the impeller which helps reduce bubble size again.

Use to do it with my FX6 but it couldn't handle the injection rate I was using and would burp.
Fitted CO2 reactors and solved the burping , CO2 injected pre reactors and post filter

 

[Akmaliano]

Except that CO2 dissolves in rubber and can make the rubber filters seals either melt or go hard (depending on rubber type) after a while. This has been seen on this forum before. Also many filters can suffer from "burping" where they periodically expel trapped CO2. Your "mileage" and experience my differ of course.

I agree that there may be mechanical/physical effects of directing CO2 through the filter, however the OP's question was specifically around the effect of such method on bacterial culture within the filter which I think are not really affected by this method of CO2 injection.

From the physical effects, I think "burping" is the most common and visible side effect. I have that all the time.

 

[Akmaliano]

Fitted CO2 reactors and solved the burping , CO2 injected pre reactors and post filter

I'm also thinking of going that route as I'm quite tired of my 306 regularly burping lots of bubbles out.

 

[HiNtZ]

I run a wet/dry as wet only. Any air locks can be relieved by unblocking the breather for a second.

 

[Aquahorti]

It can be, some studies suggest a direct negative influence as a function of CO2 levels (although small), others only indirect influence in the bacteria activity( This study is in sea water, but could give an idea about what might happen in the filter https://www.biogeosciences.net/10/3285/2013/bg-10-3285-2013.pdf). But why do it in the first place?, as far as I can tell you might as well use a reactor after the filter to get a similar effect.

 

[Edvet]

But why do it in the first place?

Lot''s of people use their filter to improve dissolving the CO2 with succes ( mostly smaller tanks and lower BPS) thus reducing the amount of hardware in the tank. I agree a reactor is better, especially larger tanks and higher BPS. I used one for my 400 gallon.

 

[Daveslaney]

Aside from the burping, could the same not be said for all the above whatever way you get co2 into your tank water?
If you have 30ppm co2 in the general water column, you have 30ppm going through the filter?

 

[rebel]

Aside from the burping, could the same not be said for all the above whatever way you get co2 into your tank water?
If you have 30ppm co2 in the general water column, you have 30ppm going through the filter?

That's what I was thinking?

 

[foxfish]

Yes but if a filter is burping it is because there is a build up of pure Co2 inside the filter.
You can see this happening if you use a clear vessel, if flow is not right and bubble count high, then there could be several inches of undissolved gas trapped in the filter.
I guess that in extreme cases the bio media could be encased in one big bubble of C02.