# FBF - Fluidized Bed Filter flow rate?



## moto_master (Jun 23, 2006)

I'm building a fluidized bed filter, and am about to buy a pump, but I don't know what flow rate I need to get. I searched but I couldn't find any thing, so I thought I'd ask people here that had a FBF about their FBF and what flow rate they have. Any one?

125 gallon, the pump will have about a 4 foot head.


----------



## moto_master (Jun 23, 2006)

P.S. I'm looking at a few different pumps. At the pet store they have a couple sump pumps, and then there's the power heads. Also looking at home depot and they have pond pumps and waterfall pumps. I'm kind of leaning towards the pond pumps at home depot, as they give more gph and are a little bit cheaper. Any thoughts / ideas / suggestions?


----------



## Mcdaphnia (Dec 16, 2003)

I have often used pond pumps. The disadvantage is that many of them have extremely long cords. They often include some kind of prefilter or actual filter which is good since it keeps large detritus out of the fbf.


----------



## moto_master (Jun 23, 2006)

Thanks Mcdaphnia, that puts me at ease on that issue...

Any one with a fluidized bed filter here want to comment?


----------



## moto_master (Jun 23, 2006)

any one?


----------



## KaiserSousay (Nov 2, 2008)

Couple of questions:
1 Do you have a sump
2 Is your FBF clear or opaque
Reason I ask, I made one out of a liquid tight storage container, clear, so when I hooked the 140gph pump to it I could see if my sand was in suspension..it was, but had to modify the 1/2pipe tubes outlet to get a more even dispersion..was getting pockets of sand.
I could use this really cheap, low volume pump, because it was right next to my sump. No real head to worry about.
BTW..when I pulled my sump out and tried it inline with my canister, the incresed pressure overwhelmed the seals on the container


----------



## bulldogg7 (Mar 3, 2003)

You can put a tee in the line going to it, then put a vale on the other line to restrict the flow just enough to push water through it to keep it suspended but not spilling over.


----------



## KaiserSousay (Nov 2, 2008)

> tee in the line going to it, then put a vale on the other line to restrict the flow


I know, you ment to have the valve before the container, to control the flow and not over power the container seals..right  
Anyhow..hey moto..wasssup..how is the fbf coming :-?


----------



## moto_master (Jun 23, 2006)

KaiserSousay said:


> Couple of questions:
> 1 Do you have a sump
> 2 Is your FBF clear or opaque


I'm building a sump. my plan is to do a siphon overflow into a sump, then have a pump in the sump pumping water through the FBF and back into the tank, in a way that makes a lot of surface agitation. I need a sump, and I wanted a FBF, but I don't have much money to be spending on pumps, so I'm doing it all in one unit. The FBF I'm making out of PVC pipe. Im going to test it out in the yard to get the flow right before I install it on the tank.

So, no one was responding so I went out and did a lot of searching, and then a lot of math. I didn't want to get a pump that was too big for the sand, but after thinking about it, and doing the math, I've decided to just buy a T and a ball valve (like bullogg7 said) so that I can just adjust the flow to the proper amount. Incase other people are reading this with the same issues I'll post my math:

1 cup 1mm sand = 8 square feet surface area
1mm sand requires 1.13 m/min flow
1gph = 0.003785412 cubic meters per hour
Divide M^3/h by 60 to get M^3/min
Multiply your m^3/min by 1.13 to get max area for fluidation (answer = m^2)
Dived m^2 by Pie, then find the square root, answer is the radios (answer = m)
Multiply radios by 2 to get the diameter of pipe required
1 meter = 39.37008 inches

Example:
560gph x 0.003785412 = 2.11983072m^3/h
2.11983072m^3/h Ã· 60 = 0.035330512m^3/min
0.035330512m^3/min x 1.13 = 0.039923478559999996m^2
0.039923478559999996m^2 Ã· 3.14159 = 0.012708048650524097m^2
√0.012708048650524097m^2 = 0.1127299811519726m
0.1127299811519726m x 39.37008 = 4.438188376351653â€


----------



## KaiserSousay (Nov 2, 2008)

Wow..I`ll just have to take your word for the math..over my head(good for you, shame on me  )
If it was me, I would have both intake and return in the sump..you could use a way cheaper pump, next to 0" head..you would still get all the benifits of the fbf, without any additional lines going up to your tank..considerabley easier to make an accurate testing bed..way eaiser for any service issues.


> so I don't want the sump to be a torrent of water gushing through.


If you have gone this far, I am sure you could manage a spray bar to dissapate the amount of current on your return.


> 10 to 12 times the size of the tank


Just another quasi legitamite number who know who came up with. Even at half that turnover rate, you would still have an excellent filtration system(IMHO)
Just my opinon, and we all know what they say about them


----------



## Mcdaphnia (Dec 16, 2003)

You do need an adjustment valve to fine tune the flow rate to just below what would begin blowing the sand out of the filter. As the sand grains bump against each other, they will wear slightly smaller, and the adjustment will have to be retuned, until a point when the unit needs new sand.

Zero head is important, not just because of efficiency, energy costs, but because it adds another wobble to the flow adjustment caused by changes in relative water height as evaporation and water changes change the head pressure. A fbf independant of a sump also adds a failsafe factor to the set up, since they can work independantly during maintenance or a problem with one of them.


----------



## moto_master (Jun 23, 2006)

Sorry for the slow responses. I'm trying to complete my senior year at college. 6 more weeks until I get my diploma!



> If you have gone this far, I am sure you could manage a spray bar to dissipate the amount of current on your return.


Yeah, I considered that, but my room mates complain about the noise because the tank is in the living room with the tv.



> Just another quasi legitimate number who know who came up with. Even at half that turnover rate, you would still have an excellent filtration system(IMHO)


I'm glad some one else feels that way. Makes me feel better about buying a smaller pump.



> Zero head is important, not just because of efficiency, energy costs, but because it adds another wobble to the flow adjustment caused by changes in relative water height as evaporation and water changes change the head pressure.


I understand what you guys are saying about zero head, but I don't exactly have the money to do this project, I'm doing because I kind of have to. Later when I have a little more money I might get another pump and redesign it so that there isn't any head. I stopped by home depot but they didn't have all the parts I needed. I think I'll have time tomorrow, I'll see about buying the stuff and getting started on it. I'll try and get a camera to take pictures and keep you guys informed. I want to thank you three for helping me out with this!


----------



## moto_master (Jun 23, 2006)

Sorry it's taken me so long to get this done. Life's gotten a little hectic here. I got it all cut out, and played with the design and tested it a few times before I glued it all together. Then I installed it, and had a few problems with leaks. I got them figured out, and fixed them. So I built the overflow out of 1" PVC, and the return out of 3/4" PVC. MY pump is a 500 gph pond pump. For the FBF container I got a 3/4" x 1 1/2" adapter, 1 1/2" x 3" adapter, 3" x 4" adapter, about 2' of 4" pipe, and 4" screw on cap. I drilled a hole in the cap and glued 3/4" pipe into it. Here's some pics. There's a lot of junk I need to clean up...

This is the siphon overflow intake:









Siphon overflow from underneath:









Siphon bridge connecting sump containers:









Sump / FBF pump intake:









FBF container:









Water return:









I found that the pump on it's lowest setting is the perfect flow rate for fine sand, and the pump on it's highest setting is perfect for heavier sand (almost gravel). I tried using a T and diverting the flow, but it made it too complicated (and I didn't have enough parts, and was too lazy to drive back to HD). I installed the shut off valve because if I turn the pump off the flow of the water draining out of the FBF carries the sad back into the pump. After installing it into the tank I found that the 1" siphon overflow could just barely handle the pump at it's lowest setting. I read that 1" pipe is suppose to handle 600 gph, but I suppose my siphon isn't strong enough to get that flow.

I don't have pictures of it, but I made the FBF cannister so that I could install a house water filter to do some water polishing. When I get some time (and motivation) I will pull them back out and paint them black. So that's my set up. Any questions?


----------



## josmoloco (Aug 23, 2008)

How loud is that overflow, get I get an entire pic(underwater). Is this a "safe system"


----------



## moto_master (Jun 23, 2006)

It's about as loud as a hang on the back filter splashing into the water, accept it's kind of a softer noise because it's a muffled drain noise rather than a splashing noise. I'm going to try and muffle it with filter floss some time soon. I'm having a problem with a bacteria bloom, so I couldn't get a good picture of it installed today, but I'll try and get you a picture of it soon. Yeah it's a safe system, as long as I don't lose the prime on the siphon. It's been running for a little over a week and I haven't lost the prime yet.


----------



## josmoloco (Aug 23, 2008)

So the noise is "gurgle" from the overflow. What would happen if you lost power and it came back on later?


----------



## moto_master (Jun 23, 2006)

The sound is like filling up a tall thin glass with water. The design of the siphon overflow keeps itself primed, even if there is no water flow. When the pump starts again, then the flow starts again on the siphon. This is most like the design that I used...
http://www.saltwaterfish.com/vb/showthread.php?t=288154

Here's another design. It still runs on the same principles though...
http://www.aquariumlife.net/projects/di ... ow/120.asp


----------



## planenut007 (Mar 21, 2009)

petsmart.com has good deals on quiet one pumps, I picked up a 4000, (1000 gph) $40 with online coupon.


----------



## KaiserSousay (Nov 2, 2008)

Glad to see your project done, looks sweet :thumb: 
Welcome to the wonderful world of "gurgle". I used this design
http://www.aquariumlife.net/projects/diy-overflow/120.asp
for mine, thought it was a more compact unit, with the least amount of pipe in the tank. 
As far as getting these pretzels to max flow ALL the air needs to be purged from the intake.








The center pipe was my intake, sorry for the bad picture. I drilled/tapped a 1/4npt hole in it, put a hose barb in the pipe, attached some tubing with a check valve so I could suck ALL the air out, you can see the check valve in the picture.
As far as the "gurgle" goes, sorry to say, never got it quiet enough for my wife`s ears..or for mine either, though most of the noise from the overflow was drowned out by the noise from her mouth.."Is it ALWAYS going to make THAT noise????" :roll:


----------

