Millions of tiny bubbles

[Maxine_51334]

I have a 65 gal tank.There are millions of little tiny bubbles in the tank. They are NOT caused by any of the filters in the tank.
The water is clear,except for the bubbles. All water tests are fine.
I have taken a sample to a biology teacher, and he said the water looked very healthy,a few bacteria,but nothing bad. Anyone have any ideas ? I have discus in the tank,2 clown loaches and a bristlenose pleco. I also have 5 baby discus getting ready for this tank,but I do not want to add them until I can figure this out.
Thanks !

 

[jonnythan]

Did you just do a water change? What do you have for filtration/circulation?

 

[Maxine_51334]

I do a small ( maybe 3 gal )water change every night,because of the discus.
I have an underground filter and a back pack filter on the tank.
I have turned off the filtration for up to 30 minutes,the bubbles do not leave.

 

[jonnythan]

Undergravel filter? Presumably you have an air pump and air stones?

 

[JDogg]

my guess is when you add new water you are over saturating the water with air, happens ever time i do a pwc too, i i only have to do one every couple of weeks, so it goes away.

 

[Maxine_51334]

Yes,we have an air pump,no air stones though. We thought it was the air stones,so we removed them. It is not from any type of airstone.