jocky

Two days ago I cleaned out my filter and when I put it back together and plugged it in it started gurgling, as if there was some air inside the filter.

The filter is an Eheim Pro II, it seems like air is stuck in there but I can't get it out. I looked at the manual and it was no help either.

I did notice one thing, The spray bar is placed underwater so there is no splashing on the surface. The bar occasionally shoots out air every second or so.

Now at first I thought the bubbles were stuck between the leaves of the plants but I looked at the other end of the fish tank and found that those plants also have bubbles. There is no way the bubbles could have reached to the exact opposite end of the tank. The would've floated to the surface and escaped the water.

My HC which is at the opposite end of the spray bar is bubbling like mad and even the crypts.

I read somewhere that the air contains more CO2 than in the water, could it be possible that the filter is spraying CO2 into my tank?

Diana K

Well, it is not spraying pure CO2 into the tank, but it could be raising the level of CO2. Likely the plants have removed whatever CO2 was in the water, and are using up whatever the fish provide rather quickly. This added source might be just enough to kick their metabolism into high gear.

armedbiggiet

Your filter have air bubbles are most likly cause by the water not full all the way when you put them back together after cleaning. My ehiem 2213 is like that too but not so sure your Pro 2 is the same or not since I had never seem one so every time I put my 2213 back I turn the quick release nob to on with as much water I can get in the tank and close the motor head in like that. When I do I did it over the sink so there would be a little water squash out a bit... that way I am sure there is not air bubbles.