I have the Penguin 350's and I always turn them off during water changes with no adverse affect. My water changes only take about 15 minutes on my 55's. Yes, as long as the wheels are damp they're fine.
Yes I agree, I just have never had a HOB that stays quiet so I have lost my faith in them for the most part. I am going to use one on the new tank to help establish it though. :thumb:B&K said:Thank you, everyone. I appreciate the confirmation that the bacteria will be fine. Makes me feel better.
JimA: Advantages and disadvantages to both, in my opinion.