Red Sea Nano Filter Revisions
Found out there are at least two revisions of the Red Sea filter.
Went to Petco and picked up a Red Sea Nano Filter. The filter was dated April 2009. It was very noisy in my tests in a bare tank with tapwater, especially with the lid on the filter. Removed excess molding flash from impeller and made sure there wasn't any crap hidden anywhere. No difference. This was going to sit on my computer desk and would be too annoying. It was louder than my 55 which has three large filters and fans for the lighting.
Swapped it out for another one. This one was dated May 2005. No noise whatsoever from this one.
Things I noticed between them. The older version has a white impeller. The new revision had a green or blue impeller. The new revision also had what I can best describe as a 'filter seeder', a very dense porous white pad that was mounted in a slot that was separate from the sponge/floss filter media. I'm guessing this is retain some bacteria so you don't nuke all the bacteria in the filter when you rinse out or swap the sponge/floss, but it is far too dense to trap any useful amount of particles, the water just flows around it, so I don't know what else it could be for.
So there you have it. You can check the date while in the store by opening the box and looking under the filter. You should be able to see it while it's still in the bag.
Can anyone else check the date on their filter and report whether or not they believe it is 'too noisy'?