Trying to inject O2 - and feeling dense

[dapellegrini]

Ok - I am attempting to inject O2 when my CO2 turns off. Here is my current plumbing:

1) Filter Intake --> Eheim Pro3e 2078 --> Outflow
2) Surface Skimmer --> Marineland 350 Canister --> AquaMedic 1000 --> UV Sterilizer --> Hydor Heater --> Outflow
3) Pressurized CO2 tank --> Split to Diffuser placed under ROI 50 powerhead for misting and AM1000 Reactor

So I have added a T and some check valves in the airline from my CO2 cylinder. When the CO2 turns off, I have an air pump that turns on. PROBLEM: it does not create enough pressure to get the O2 into the reactor or the diffuser. I have tried a couple different sized Air Pumps with no luck.

Needless to say I am feeling a bit dense. Some possible solutions:

1) Bigger air pump - I am doubtful this will fix my problem... ?
2) Isolate my air injection to either the Reactor or the Diffuser - which would take less pressure to run? The Diffuser is a small ceramic one off of ebay.
3) Add a venturi somewhere in this mess? If so which one would be the easiest to plumb in and how would I turn it off at night?

I am hoping for some simple and practical advice.

 

[pepetj]

The old trick of using an airstone and injecting atmospheric air works fine. Keep in mind around 20% of the bubbles is O2, the rest plain inert Nitrogen gas. Wether the problem is solved by de-gassing CO2 or adding O2 or both I don't know for sure but this method has worked pretty well in my planted Discus tanks, where temperature per se is a limiting factor in reduced dissolved oxygen levels.

Fish respiration and behaviour is what I mostly I use to check for adequate levels of dissolved O2 although if needed I have a Hach Oxygen test that works pretty well.

Pepetj
Santo Domingo

 

[dapellegrini]

This is also for a discus tank. I have an air stone in there now but would prefer to work it inline.

 

[dapellegrini]

Is no one else doing this?

The problem with the air stone in a rimless tank is that it creates a lot of fizz which gets everywhere I don't want it, creates calcium type deposits all over, etc. I wonder if my Magnum 350 with all it has inline already will create enough pressure for a Venturi to work? Seems that most Air Pumps only do between 4 and 8psi - which just doesn't seem to cut it...

 

[Tug]

Hi dapellegrini,

I have been thinking of using something Pat has on his CO2 reactor for a purpose such as yours. It is a Venturi T fitting like this one, http://flexpvc.com/cart/agora.cgi?product=PVC-Venturi-Tees The idea is to place it on the return to the tank just below the surface in the hope that it would suck in some surface water and mix it with the water coming from the CO2 reactor. When the CO2 is off but the pump is still running it should continue to circulate surface water to the lower portions of the tank improving O2 levels, but I haven't tried out my idea yet.

Or, I suppose you could try an air stone that creates larger bubbles and less fizz.

 

[waj8]

I use an air stone in my sump at night. One of the advantages of a sump over a cannister. If you are feeling adventuresome tap an airline into your filter intake line and allow the filter to suck a bit of air. You would need a little valve on the airline and a solenoid set on a timer. Never done this myself but you could try it and let us know how it works.

 

[waj8]

I think cannisters operate at less than 10 psi. You can find out by looking up the maximum pumping height. If it were 10' then it would be around 5 psi. and so on. If you are feeling adventuresome try tapping an airline into the intake line of the of the cannister. You would also need an air valve and a solenoid to open the airline on a timer. Some will say this will be bad for your impeller but that is not necessarily so. I have an air stone in my sump. One of the many advantages of a sump over a cannister.