Originally Posted by novahobbies
http:///forum/post/3298147
A wet-dry filter is a type of a sump - but not all sumps are wet-dry filters. And contrary to popular internet belief, yes you can CERTAINLY keep a reef environment with a wet-dry filter. I do! Boy, I've been meaning to write an article about this....it's a pet peeve of mine.
A wet-dry filter, also known as a trickle filter, works by passing water through an overflow (drilled, HOT, whatever floats your boat) and down into the filtering mechanism. There are different kinds, but I'll try for the basics here. Your tank water first flows through some form of physical filter - a sock, floss, that sort of thing. Many of the pre-made wet-drys have a tray that holds a sheet of filter floss right under the tank outlet. There is usually a spreader bar of some sort as well to take the concentrated flow and increase the water's surface area. After it passes through the physical and sometimes chemical filter pads, the water trickles down into a large area containing bioballs. The bioballs work by utilizing a large surface area per ball to grow nitrifying bacteria on. The aerobic bacteria that metabolize ammonia and nitrite (nitrosomonas sp. and nitrobacter sp., respectively) are encouraged to grow on the surface of this media because both types of bacteria favor a high-oxygen environment. Your tank water, properly filtered from most particulates by the floss above, trickles down through this bacteria-laden media where it is "washed free" of any ammonia and nitrite. The cleaned water then collects at the bottom of the filter, where it can go through a protein skimmer, refugium, live rock area, or whatever you have room for in the rest of your filter. Of course, your return pump send the water up to your display tank and the process begins again.
Now, you'll hear people and internet sites say that trickle filters are "nitrate factories," and that you should immediately remove the offending bioballs and run some other media in their place. Nonsense, I say. However, I do agree with the first accusation: trickle filters ARE nitrate factories. It's exactly what they're supposed to do!! Go back and re-read the description. Bioballs use their surface area and high O2 environment to cultivate aerobic bacteria to remove ammonia and nitrite - they do nothing to remove nitrate, as this chemical is most often metabolized by anaerobic bacteria. It's hard to cultivate anaerobic bugs in this kind of filter! Your nitrates should be controlled by the live rock in your tank, in another area of your sump using live rock, and of course by regular water changes.
I think people run into problems with trickle filters because of lack of proper maintenance. I'm not accusing anyone here, but this is what I've seen from helping take care of friends and neighbors aquariums. There needs to be a good physical filter before the bioballs. I've seen where people only use one sheet, or they cut it haphazardly and it allows unfiltered water to sneak down between the pad and get to the bioballs directly. The filter floss needs to be packed snugly in place so NO water can get down without going through the floss. Also, (and this is usually concurrent with the floss issue), the bioballs may have become clogged with detritus and lose their surface area for filtration. This is an easy thing to fix, and something that should be done once ever couple months anyway. Rinse those balls!
Do it at least 3 times a year...my schedule is every other month. Save some tank water from a water change in two tubs. Take out your bioballs, pour them into tub A, swirl them around until they're clean, and scoop em out and rinse again in tub B. The water in tub A may look gross if the balls haven't been cleaned in a while, but if you're keeping a good filter floss media on top of the bioball chamber the rinsewater won't look too bad.
So, that's it. Just follow those two suggestions regarding sump maintenance, and you shouldn't ever have a problem with your bioballs going south on you. You can certainly keep corals while using a trickle filter - I haven't seen any issues with the coral in my seahorse tank. I run a trickle filter in there, and my levels for the big three are 0, 0, and between 0 and 5 for nitrates. I hope this helps!
Thanks, that explained allot, but I don't think it is anything like the filter I found except the bio balls part, have a look and tell me what you think. LOL...I think you should write that article, very informative..
