Fluidised Sand Filters

[sianeds]

I just bought a load of marine stuff from the LFS I'm working at. One of the things that comes with the ackage is a fluidised sand filter. It is huge!!

I have very little idea how it works though

Can anyone explain the basic principles to me?

 

[andywg]

It works by having enough of a flow to keep the sand in suspension, but not enought flow to blast the sand into the tank.

Having all the individual particles of sand in the water column gives a huge amount of surface area in a tiny space.

FSB are very good for getting ammonia down to nitrate, though have one problem. Once the flow stops the sand will compact and it is believed large amounts of bacteria die off quickly due to a lack of oxygen.

 

[sianeds]

I guess I need to make sure I have no powercuts

Let me see if I've got this straight, bacteria will colonise the sand and help with the nitrogen cycle right? I'm thinking it's part of the shops setup as they tend to keep shop display tanks overstocked and so it deals with the ammonia more efficiently (space wise) than a huge sump tank filled with LR etc.

I'm guessing it won't be neccessary in my 125gal setup unless I choose to keep very messy predatory fish etc. Would a good sized DSB be ok instead??

 

[SkiFletch]

Yeah, a good sized DSB, especially a remote DSB would probably be a better option. You're exactly right that fluidized beds are best suited for LFS' that overstock their tanks. Not always practical for the home hobbiest.

 

[sianeds]

Ok so I have a fluidised sand filter going cheap

I will be having a DSB in my sump, the biggest I can fit.

Just as a side note....If I was to use normal aquarium sand in my display it wouldn't have any buffering capabilities. So...Would a remote DSB of coarse aragonite substrate (which I have in my current tanks) do the buffering for me? In addition to a DSB with finer grade sand for biological filtration.

 

[SkiFletch]

It would be tough to quantify the effect. Sure it would buffer, how much is tough to predict...

 

[sianeds]

I like the look of finer sand and it's much easier to keep clean (and it's cheap!)

I suppose I'll wait until the tank etc is in place and see what I can do then.

Thanks for the help guys