I think this is a great idea for a thread also, but like Mojo, I've never found it an easy task of putting it all together. Over the years, we have tried numerous methods to keep our tank's inhabitants alive. i think Mojo simply wants to go over the various means of reefkeeping, with the emphasis on the methods they used for filtration.
The very first of them all was actually the sand bed. Back in the early 1900's a guy was able to get sanddollars to breed after he tried using live sand from the ocean. That was a simple experiment with the "tank" being a mason jar, with a handful of sand and ocean water, changed daily.
The first "hobbyist" filter available for saltwater was the undergravel filter. This was a god-send at the time when it was nearly impossible to keep fish alive for long. It works by mechanical and biological filtration mainly, with chemical being added if needed. The crushed coral acted as a buffering agent, and also as a place for bacteria to colonize, just like in fresh water tanks. It also acted to catch large particles of waste which then would get siphoned out on a regular basis. Bacteria would thrive in the pocket of water under the plate, and the airstone both oxygenated the water and provided a means of drawing water through the gravel.
Cons of this method are consistent water changes to remove debris, as well as the need to rip up the UG filter plate when enough waste accumulated under it (which will inevitably happen). It also does nothing for breaking down nitrates, meaning alternate methods are needed to control this. It does not favor burrowing fish or many critters.
From there, we flocked over to power filters of all sorts. While these do great for freshwater fish, it's not the easiest in a marine environment. I'm also going to include canister filters, since they work ideally the same way as a PF, only hidden under the tank, and a bit more powerful. Powerfilters are a step up from UG filtration. They have the ability to trap waste on a pad instead of using the gravel bed. This enables the waste to be removed on a much easier basis, and allowed for a cleaner (healthier) environment. It still handled mechanical and biological filtration, but almost always adds Chemical (carbon) filtration as well. Some PF's started using grids or wheels to increase the amount of bacteria-driven filtration the filter can handle, but they still cannot achieve reduction of nitrates.
Pros include being small, quiet, and easily cleaned. Can handle nitrogenous waste, up to a point. Has mechanical and chemical filtration also.
Cannot handle nitrates, or have as much bacterial filtration as a substrate bed. Must replace cartidges on a frequent basis ($$). Must be cleaned regularly or diminishing returns result.
Then we move into the wet-dry filtration. This basically was an upgrade from the undergravel filter, but at the same time had some of the same downfalls. W/D's do nothing to help control nitrates, meaning denitrification is not coming full circle, and exportation is not being achieved optimally. The emphasis was put on aerobic bacteria to handle ammonia and nitrite. At the time, Nitrates were not suspected of being extremely hazardous.
The W/D allowed a bigger volume of water on the same size tank, which began to provide a bit of stability to our tanks. It also allowed us to start REMOVING items from our tank, and hiding them in the W/D. This was a main reason for the popularity of W/D's IMO.
Drawbacks are the inability to handle nitrates, meaning alternate methods are needed. Tended to be difficult to setup properly. Also fairly pricey compared to previous methods of filtration.
After this came the plenum and the DSB, both having benefits and drawbacks as well. In either case, we moved into being able to now handle the full denitrification process. Nitrates for the first time can be broken down to a gaseous state and exported. For this reason, I usually group these in the same category, even though they are distinctly different in thier own ways. Most of the benefits and drawbacks of these have been covered so far, so I'm going to skip these for now.
Then we move into alternate means of filtration, such as the infamous skimmer, algal filters, refugiums, xenia farms, mangrove sumps, etc.
These are mostly ways of adding the missing component to one of the above methods. In most cases, it's a means of nitrate and phosphate uptake, but it can also manage dissolved organics (DOM) or possibly even inorganic waste.
My fingers are starting to get a bit cramped, but there's so much more I can add. Too bad I can't type as fast as my brain thinks it
Take some of this into consideration, maybe ask a few resultant questions? Give me a little more direction and I can offer a ton more on the subject.
great thread Mojo!
Cos
