I'd also like to add that T1's tank is a 360 gallon, filtered by 2 eheim pro 3's, and his fish are some of the best and healthiest I've seen in person, and his tank was crystal clear. He also kept sensitive fish, rays and uaru nandos when I visited.
A lot of people's opinion seems to be canisters are insufficient for a tank that size, and you need a sump, but his tank was mint.
I agree most overflows fail at keeping the tank bottom clean. Several years ago, I bought a tank that uses a double-wall overflow corner box. I really like the way this setup keeps the bottom clean. The inner wall is the same as most w/d filters incorporate. But, this setup has an outer wall that pulls water from 1" off the bottom of the tank. Then, the water flows over the traditional wall. The only maintenance concern is keeping the large grill from clogging. But, cleaning it during my regular water change seems to do the trick. I retro-fitted a couple of other tanks by adding the outer wall and grill. So far, so good on the tanks they're running on.
Another plus of a wet dry is that it can skim the surface of the tank for protein film.
Canisters cannot do that without additional apparatus.
To me, a wet dry is my bio filtration while my 2 canisters ( Fluv 404 ) serves as my mechanical filtration. As far as changes, i did switch from canisters to wet dry but i cannot
offer concrete data as i havent tested my water before and after .
This is a great thread. I have also wondered which set-up was most
beneficial for the fish. I have also considered going from the XP3's which I love to
the much larger and more powerful FX5 or Eheim Pro 3. The debate is still
very much a toss up.
It's a personal choice I feel my 3 XP3 's do a great job and are easy to clean, although mine are loaded with Seachem Biofilter Media and not set up as they come from the factory. I will agree with you the output seems weaker than the competitors, but I'm more interested in contact time with the media then moving water. They provide a good bang for the buck. This is a good thread because as my bio load increases in my large tank I've debated on going with a sump unit , to increase it's holding capacity. Keep the info coming...
With canisters, you either love em or hate em. I've had them, don't like em. Wet-drys are sooo much easier to maintain. The only canister I would consider using on a really large tank would be a bead filter thats made for ponds. You can backwash those suckers, easy maintenance, really nice.
Actually there is one design called the 'overflow and underflow' (shown diagram below). This kind of design has been commonly used for the customized sump tank.
I agree most overflows fail at keeping the tank bottom clean. Several years ago, I bought a tank that uses a double-wall overflow corner box. I really like the way this setup keeps the bottom clean. The inner wall is the same as most w/d filters incorporate. But, this setup has an outer wall that pulls water from 1" off the bottom of the tank. Then, the water flows over the traditional wall. The only maintenance concern is keeping the large grill from clogging. But, cleaning it during my regular water change seems to do the trick. I retro-fitted a couple of other tanks by adding the outer wall and grill. So far, so good on the tanks they're running on.
