sump VS wet/dry

[Ross]

Hi, this is Ross' dad (Glenn). In an effort to keep a general idea of how and why things in his aquarium work I would like to ask a question about his filiter system. Ross wants to get rid his wet/dry and change to a sump and I don't know any of the details about why these kinds of things work. When I look at his wet/dry I can see stuff that "does something"...mesh filiters, bio-balls, etc. When I listen to his description of the sump it doesn't seem like there is anything in it that would "do anything". Is there more to a sump than just a container to hold water? Doesn't it need something to make up for what the wet/dry was doing? We are going to build a refugium...will that do what the wet/dry was doing? If so then do we still need the sump? What is the difference and do we need both?

Thanks for helping me understand!
Glenn

[Tim Marvin]

The refugium will work a thousand time better than the wet/dry or sump. Wet/Dry produce Phosphates which are bad for the system. Refugiums remove them with caulerpa and other macros. In my opinion refugiums and skimmers work best.

[::pete::]

I use to use emperors on my tank and could never get the nitrates to go away. After I set it back up and added a refugium/sump using no mechanical filters I can not even get a reading for nitrates using a salifert test kit. In addition all the other water parimeters are in check and I dont have to add or compensate other than normal water changes. It doesnt seem possible but there isnt a mechanical filtration unit on natural reefs.

This might help. (http://jjgeisler.com/reeftank/55g_sump-refugium2.htm)

[matt]

Glenn;

Basically a wet/dry filter is a sump, meaning it's a container that allows you to drain water from the tank, and recirculate it back up. But, a wet/dry filter also has a chamber where the water trickles down over "bio-balls" or something similar in a very high oxygen environment. The bio balls provide a place for bacteria to colonize which convert ammonia and nitrite into nitrate. This is needed for a tank without a natural place for these bacteria to colonize. But, now most reef tanks use a high quantity of sand and rock, which provides the place for this bacteria to colonize. There's one big difference; in the wet/dry there is no place for other strains of bacteria that prefer lower oxygen content to colonize. These bacteria are necessary to convert the nitrate into free nitrogen and bubble out of the system. The sand and rock, however, do provide areas of lower oxygen content. So the bacteria population becomes more balanced and provides a way for nitrate to be processed out of the system. In the old days of fish-only, nitrate concentration was not really a problem; fish can tolerate it. But in a reef its bad news; corals can't tolerate it, and algae use it and proliferate, eventually taking the tank over. Removing the bio-balls and allowing the natural substrate to colonize results in much lower nitrate.

Here's where the refugium comes in. There's always some nitrate, and another nutrient, phosphate, in aquariums. It's simply unavoidable. The refugium, among other things, gives you a place to grow macro algae like caulerpa; this stuff uses the residual nitrate and phosphate that builds up; preventing nuisance algae from taking over the main tank. Periodically some of the caulerpa is taken out of the refugium and discarded, hence removing the undesired nutrients.

Typically the sump and refugium are either separate containers, or the same container divided into sections. This allows you to regulate flow, because often the optimal flow through a refugium is lower than what you would usually have in a sump. The lower flow lets you have a sand bed and develop a thriving community of micro-critters like mysid shrimp and amphipods and worms of various types. These animals reproduce and their larvae is swept into the main tank, providing food for many of the inhabitants.

Hope that helps. Sounds like your son is on the right track.

[Yano]

Thanks Matt, I learned alot from that :D

[Ross]

Thanks for all the info guys. (this is ross)

I tell him that wet/drys are nitrate traps and i needed to just have a sump/fuge. I told him all about how the fuge removes nitrate and other nutrients. He just didn't understand what the sump was for. I guess he just needed to hear it from someone else.

[Ross]

Cool, thanks guys. I knew Ross knew what he was talking about, but he just wasn't convincing me what an empty sump was going to do.

Glenn

[Andrew]

Ross (or Glenn)
If you already have a wet/dry, depending on the size, model, and flow through it, etc, you could potentially remove all media, install lighting (several normal output flourescents, or a pc retro kit over it), along with sand bed and live rock if you choose, and you'd have a refugium. This could be done gradually if money is an issue (You could add each component gradually).

HTH

Andrew

[Andrew]

A sump is basically an extra reservoir of water which helps system stability (dilution of nutrients and waste, and place to put heaters, pumps, skimmers, etc); refugiums and wet drys' are variations on this idea.

andrew

[dan]

very well put matt.

[GaryP]

I'm thinking that we definitely need to add a pretty good module on filtration systems to the nutrient export training class. That actually might be a good idea for the second class (after water chemistry). Do we have any volunteers for instructors?We might shoot for that one in Mar./Apr.

Gary

[GaryP]

Here is a pretty good article from Seascop that discusses a comparative study of different filtration schemes.

http://www.marineland.com/seascope/ss2003_issue2.pdf

What I got from this is that the best method for nitrogen control is having macros and lots of live rock to use the ammonia before it even goes through the nitrogen cycle. A definite plug for refugiums. The other thing I got from it was the importance of a good skimmer for TOC control.

Gary