I have a 20 gallon Nuvo Nano. I'm just curious if anyone has any suggestions for a UV sterilizer, not too big, not too small, what brands/models should I look for and stay away from? Thank for all of the help yet again!
I can't think of any reason you would need one on a tank that small.
They are marginal at best when fighting parasites (most units are designed wrong, they can help manage/prevent an outbreak, but won't "cure" one) and really are only good at clearing up bacterial or free floating algae blooms, both of which can easily be managed in your tank via water changes.
Save your money or invest in lights or something that will give an actual benefit to you.