Fluidized bed filters
- Thread starter FuEl
- Start date
David M
New member
I have been interested in FBF's for a long time now, still not sure. What I keep hearing/ reading is that they are a double edged sword, on the one hand highly efficient and able to rapidly adjust to changing conditions, on the other hand absoulutely deadly if they collapse. It is the filter of choice at all the wholesalers but then all they risk is the fish in stock at the moment which are easily replacable. Our broodstock is very valuable and not so easily replaced. I may go that way for grow out but I doubt I'll ever set up a fbf on my broodstock systems.
purplehaze
New member
Yeah exactly...and it consumes a lot of O2 dropping the pH level specially in BB systems..got to keep an eye on it..
Dman
New member
A rapid build up of nitrates is far, far less dangerous than a rapid build up of ammonia or nitrites, which is what FBF's are good at doing, converting ammonia and nitrites into nitrates.
For example, I've moved over 100 fish this last week and next week I'll add probably 250 fish to the system, with an FBF I don't have to worry about wildly fluctuating bio loads. You want to convert your nitrates? Try an RDSB (remote deep sand bed) Dropped my nitrates from 300+ to 60-80ppm with a 45 gallon drum.
For example, I've moved over 100 fish this last week and next week I'll add probably 250 fish to the system, with an FBF I don't have to worry about wildly fluctuating bio loads. You want to convert your nitrates? Try an RDSB (remote deep sand bed) Dropped my nitrates from 300+ to 60-80ppm with a 45 gallon drum.
purplehaze
New member
Nitrate build up is pretty fast...do you only have fish in this system?
It won't build up nitrates any faster than any other well established and fully functional aerobic biological filter
Where it gains an advantage over trickle filters is in two aspects, it takes up considerably less space, and it responds faster to fluctuating bioloads. However, it simply can't produce more nitrates as that is directly tied into how much ammonia is being produced by the fish, something that doesn't change by what kind of biofilter you use Hmm, thanks for the inputs. 
My breeding system is unorthodox in that the broodstock, larval rearing and grow-out are going to be all interconnected.
I'm more concerned with regards to nitrates as it is very lethal to shrimp larvae. I just got my denitrator set up today, it functions just like a FBF just that its designed to cater for anaerobic bacteria. Imagine fluidizing sulphur beads.
Considering the pros mentioned here on the FBFs I will probably be adding one in the near future. Thanks for the feedback once again.
My breeding system is unorthodox in that the broodstock, larval rearing and grow-out are going to be all interconnected. I'm more concerned with regards to nitrates as it is very lethal to shrimp larvae. I just got my denitrator set up today, it functions just like a FBF just that its designed to cater for anaerobic bacteria. Imagine fluidizing sulphur beads.
Considering the pros mentioned here on the FBFs I will probably be adding one in the near future. Thanks for the feedback once again.
"Umm fish?"
Premium Member
I sure hope that it's fluidizing the sulpher beads with some kind of recirculating pump and not with oxygenated water straight from the tank. And that the recirc. pump is not drawing any air into the mix.
purplehaze
New member
Exactly my point and high nitrates won´t let the eggs complete their development ..which means no larvae...that is why I asked which animals are going to be kept in the system
To "Umm, fish?":
Yes you got the design right there. The water feed is via an airline tubing with a control valve. First chamber consists of sulphur beads. The second chamber consists of some ARM media to buffer the water before it is dripped back into the tank.
To purplehaze:
You're correct on this point. My shrimp larval survival has been pathetically low. My nitrates are like 50 ppm now. Hope they drop to zero within a month. Meanwhile have been using denimax (some Japanese product which claims to promote a bacterial bloom to reduce nitrates) in conjunction with the denitrator and doing water changes too.
Once my nitrates can be brought down to zero, will install the FBF!
Yes you got the design right there. The water feed is via an airline tubing with a control valve. First chamber consists of sulphur beads. The second chamber consists of some ARM media to buffer the water before it is dripped back into the tank.
To purplehaze:
You're correct on this point. My shrimp larval survival has been pathetically low. My nitrates are like 50 ppm now. Hope they drop to zero within a month. Meanwhile have been using denimax (some Japanese product which claims to promote a bacterial bloom to reduce nitrates) in conjunction with the denitrator and doing water changes too.
Once my nitrates can be brought down to zero, will install the FBF!
"Umm fish?"
Premium Member
Have you tried table sugar? It's the same principle, but a whole lot cheaper (I'd wager). I have not done this so I have no data, but the idea is to VERY SLOWLY start putting a very small amount of sugar into your water. SLOWLY ramp up. Did I say slowly?
