I should have listened to NYgiantsRP. I ended up getting the U4s and the media capacity is basically nil plus the flow is way too strong in the wrong direction (right across the tank) - my poor Mystery snail gets his shell knocked around by it in the one tank and I'm sure it'll be too much for the goldies.
I think am going to bite the bullet and get an AC
110 to couple with the Eheim 2217. I'll use the Eheim as my primary bio filter and the AC
for mechanical + Purigen. I figure the AC
will be better for Purigen because it'll be easier to change out the bag when it gets exhausted.
I'm going to put the same combo of filters on my 55g tropical community, too. I can buy media/sponges/floss in bulk this way for all of the filters.
I'm going to put my Penguin 350 onto my hospital/quarantine tank and I think I'll be all set.
Do you think the AC
+ the Eheim + the Hydor pump will be too much current for the goldfish? Is that all overkill? Should I nix the pump?