Biofilter instead of skimmer?

barrysalt

New member
Have a chance to purchase a 1200 gal tank. Owner uses a biofilter which sits over the top of tank, water pumped to it to filter through bioballs and filter media. He doesn't use a skimmer. Claims it is not necessary. My thinking is that a skimmer removes organic and inorganic particles, and has nothing to do with a biofilter. Anyone have experience in this type of system, or your thoughts?? Thanks...
 
I wouldn't. A biofilter runs high nitrate, which is incompatible with a reef, and not good for fish. It takes live rock and sandbed to break the nitrate down to nitrogen, which is where it needs to go. It is so serious for a reef that I don't even keep sponges in the system, because they can also spike nitrate.

A skimmer removes spare amino acids from a system, so it is not a filter in the ordinary sense. It is definitely useful for a marine tank, but a very small system might get by without; and reefs other than sps don't need a top-of-the-line skimmer because corals are also filters, and will enjoy a certain amount of extra nutrient, but not too much.

Some people also run filter socks, which are simply a dense cloth bag that has to be removed and cleaned often, to get the least particulate out.

Bioballs are useful in a fish-only, but frankly, I find a fish-only not as easy as a middling sort of reef, which lets you know (by folding up) whether your water is needing a test and correction. Fish just tough it out until they go belly up: so if you keep fish only, you do need a strict testing schedule.
 
No tank exists without a biofilter (either dedicated biomedia such as bioballs, or simply surface area provided by sand and LR), gotta get rid of the ammonia. Skimmers help greatly by removing organic compounds before they enter the nitrogen cycle. You can run without a skimmer, but you'd see a much faster accumulation of nutrients than you would with one.
 
Thanks for your input. Although I may do a FOWLR tank, it seems you would definitely run a good skimmer with or without the biofilter system. I agree, and will try to do just that!
 
There is one type of tank that would work very well with a 'nitrate factory' - a marine planted tank, with seagrasses and/or macro algae. I have such a tank, and I have recently begun nitrate dosing to feed the plants. If I had a sump, I would definitely reinstall my old wet-dry trickle filter to aid in this regard.

Otherwise, a deep sand bed would help your tank process nitrate.
 
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