tiny bubbles

[Plonk]

I have a large waterfall style bio-filter, which I had it set on the slowest water flow into the tank. The noise was driving us nuts during the night even though the water level was high to minimise the noise. So last night hubby put a ice-cream lid up under the waterfall so now the water doesnt make any noise at all. I woke up this morning and there seems to be lots of tiny bunched up bubbles all over the surface of the tank. Have I done a BIG wrong doing the home job last night??

 

[ben_tajer]

Probably not, little bubbles can accumulate for a bunch of reasons. In an outdoor pond they can happen from too many leaves on the bottom of a stagnant pond causing methane or other gasses to build up, but this is unlikely in an aquarium. If you have any plants they could be the source, or even the filter it self. I wouldn't completely right off the chance of there being something wrong, but I can't see how a mechanical adjustment to your filter output would dramatically alter the tanks water chemistry, let alone in a way that would cause harm to your pets. Especially with axolotls it's probably a good idea to try and dissipate the water out put, any current that's too violent will stress them.

 

[Plonk]

Since I did the home job last night my babies have been venturing right up the end where the filter is. So I know I have slowed the current down.
I have no plants in the tank either.

 

[Jennewt]

It's probably just a surface film trapping bubbles. Not serious.