air is trapped in pump due to pearling/saturation

Martin

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Mar 8, 2005
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hi guys.

a frustrating question...

My tank is growing fine, no probs. etc.. only 1.

it's not that my tank pearls a lot, but it does produce a lot of oxygen.

Apparently this is bring trapped slowly, accumulates, and then my pump gets a fit trying to smash all the trapped air.
This happens during the day, but mostly at night (when the air has had time to build up).

I am 99,9995% certain it isn't a leak somewhere in the pipes..

Actually a friend has the same problem

Anyone experienced the same?
Any ideas on a fix?
 

Tom Barr

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Jan 23, 2005
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It can be a few different gases, air, but also CO2, particularly at night.

CO2 is not used at night, there is still a fair amount in there at the evening's change when you turn off the light.

So when plants do not use it, the gas can build up in trapped places along with other gases. It degasses fairly readily. Filters have a lot of biomedia also, and turbulence, shear from the impellers, plus...........lots of bacteria and plenty of O2 which the bacteria use to make plenty of CO2, pretty much like us/our lungs.
O2 as well builds up and it's rather tough to dissolve. Same for air, N2 etc.

Simply cleaning the filter good ought to take care of things. This same process occurs in CO2 reactors, the idea behind the venturi loop is to purge this trapped gas.

This can be done on a filter and many have such things => priming the filter when you restart them etc. Some do not. Sediments release more gases at the end of the day also(CO2 mostly, but perhaps O2 from excess root exuding/leakage).

Night time aeration might blow off the excess gases in the tank and help purge the gas indirectly. Also, mist aeration can have a good effect by adding more current, sticky adhesion of the microbubbles to algae and waste, that helps get smaller particles to filter out.

Much like a clarifyer or flocculant.
If it's air in the filter, then adding aeration would increase this.
If it's excess O2, then this will reduce it some, or if it's CO2 excess, then it will also reduce it.

Just ideas here, little evidence of what the gas is/is not.
A syringe can be inserted and the gas can be withdrawn and analyzed to see what it is. Several systems and tanks should be looked at to see what differences there are.

Not really a pressing issue however.

Regards,
Tom Barr
 

Martin

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Hi Tom.

You may be right.
I've never experienced it before, which is why it has me wondering.
Cleaning the filter does not appear to help though.. unfortunately..

Hm, I'll have to start fiddling...
 

TheKillHaa

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Oct 31, 2007
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i have this issue on several filters along tanks under sunlight, a lot of air is trapped and i can see thru filters (i have one magnun 350), reason i conclude is a lot of gases disolved in water, plus the efect of cavitation, (implosion of water by pump's impeller, creating bubles)
this is no driven a really problem, as impeller in that filter is at bottom, so water still runing thru almost 90% of filter... what i do, if i have time to doit, is turn off the filter 10 secs.. to let te air drain by itself, and turn again on. at least is a little less noisy.

this is not a solution neither in your case, but just adding more ideas ;)
 

Tom Barr

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TheKillHaa;37983 said:
i have this issue on several filters along tanks under sunlight, a lot of air is trapped and i can see thru filters (i have one magnun 350), reason i conclude is a lot of gases disolved in water, plus the efect of cavitation, (implosion of water by pump's impeller, creating bubles)
this is no driven a really problem, as impeller in that filter is at bottom, so water still runing thru almost 90% of filter... what i do, if i have time to doit, is turn off the filter 10 secs.. to let te air drain by itself, and turn again on. at least is a little less noisy.

this is not a solution neither in your case, but just adding more ideas ;)

If you use a digital timer that can shut off a filter for 1 minute etc, you can do this 2-3x and purge the gas by shutting off the filter for a few minutes each day around that same time it builds up.

A similar thing can be done with the Reactors etc. 10-20$ solution.
I modify the reactors to suck out a pre set level inside(see dual DIY venturi reactor thread in the articles section here) once the gas builds up enough.
This gas is sucked into the suction side again, where it is shredded up again by the impeller, then exits through the system.

Then you get aggressive "misting".

Regards,
Tom Barr