Sand filters?

[jerseydiablo]

Anyone use a fluidized sand filter?

good/bad?

It's the same as RDSB correct? And I've heard a cannister filter can act the same way?

 

[Carlo]

I have one. I think I've one of everthing.

Good or bad depends on what you are trying to do with it. My personal opinion is that it's not a good addition to a reef tank. Let me see if I can explain a little bit about how they work and it might make better sense to you.

The idea behind them is that the sand in the filter adds a lot of volume to the filter media. This volume can support a LOT of bacteria to break down Ammonia and Nitrites into Nitrates. Because there is so much volume you can support way more bacteria then your system needs. This is ideal for dynamically changing fish loads where the amount of bacteria needs to increase and decrease based on bio-load. In a way you can think of it as a wet/dry with tons on BIO balls.

If you run a system where the Nitrate levels aren't that big a deal (fish only) then it's a great filter. It "can" be a good filter on a reef system if you have a large refugium to export the Nitrates out of the system.

The general problem I see with them on a reef setup is that it throws off the natural biological filtration system. You just can't get better then live rock as it support both types of bacteria needed to convert ammonia/nitrites into nitrates and also to break down nitrates in the low oxygen porous parts of the liverock. This latter set of bacteria works best when neighboring bacteria breaks down the ammonia. When you add a fluidized bed filter it will easily take over much of the former bacteria since it's an ideal bed for the high oxygen based bacteria to thrive. This in turn makes breaking down the nitrates even slightly worse.

To answer the second part of your question. No it's the direct opposite of a remote sand bed. The fluidized bed filter is a high oxygen based filter where all water passes through the sand filter. In a remote sand bed you are creating a low oxygen based environment to process out the Nitrates. The remote sand bed is a very thick sand bed and water only passes over the surface and not through it like the fluidized sand bed. This allows the deeper levels of sand to become anaerobic (without oxygen) which fosters the bacteria that live in the oxygen depleted environment to break down the Nitrates.

So in a nutshell each of these is trying to build up a population of different types of bacteria.

I hope that was clear enough to get the idea behind each of them without going into to much technical jargon. If not let me know and I'll elaborate.

Carlo

 

[jerseydiablo]

Wow! Thanks cayars, alot to take in but very informative reply. I'm too tired right now to actually take it all in and if I have any more questions I'll reply sometime tommorow.

Thanks again

 

[Carlo]

No problem, I just tried to give an overview without getting to technical. If you have any questions after reading it just ask. I know others as well as myself have them and can chime in with advice/help on them.