Bacterial Bloom

[Stark]

So about a week ago I transferred my betta from a 1 gallon tank to a 5 gallon tank. The whole time he was in the 1 gallon, the water was crystal clear.

Within 2 days of the transfer I have had major cloudiness and lots of film on the top. There is a filter, but I'm not using it because it's too strong. I did purchase a smaller one and am hoping that it will work better. I should be able to try it out tonight.

I've done a couple of 75% water changes and it hasn't helped. From my research on here it appears to be a bacteria bloom. I've tested the water and there is absolutely no ammonia, nitrites, or nitrates so I'm not too concerned that it's harmful for him.

But my question is why is this happening in the 5 gallon when the 1 gallon did nothing of the kind? Wouldn't a larger tank be even cleaner than the 1 gallon?

Just really curious.

[Olympia]

Not sure about the last question, but generally water changes don't help, if not make things worse. Blooms usually clear up on their own within a few days.