# DIY Fluidized Sand Filter



## Zvander (May 12, 2012)

OK - so speaking of DIY - I've been giving it some thought (which, at this point, is making my brain hurt) and here is my idea. Any feedback is appreciated.

My idea is to *build a fluidized sand filter* out of 4” thin-walled PVC pipe, 3' tall. Then use 4” flat PVC caps for top and bottom. I'll use 3/4" bulkhead fittings in the top and bottom. On the bottom end I'm going to plumb in the incoming water (exiting) from the pump (I'm thinking about using a 'Quiet One -Model 1200' pump to circulate the water - need a pump that can be external/dry). 

*Top of filter: *
On the top of the filter I will have a 4” cap with a 3/4" bulkhead fitting in it. I will leave the inside, top; open (no pipe extending from it). On the outside, top, I will have a union and ball valve then a check valve (so there is no chance for siphoning). That will then get plumbed with 3/4" PVC through the wall on the shop side of the basement to the finished side, where the 90 gallon (fresh water) aquarium is located. Then I will have it return into the tank (with possibly a 90 degree elbow).

*Bottom of Filter:* 

*Intake Side of pump: *
I will run 3/4" PVC pipe with a strainer (protected with a sponge prefilter) from the tank (through the wall) down to the pump. I will add a ball valve (in case I need to disconnect the pump), then I will connect the return line to the pump with a union (for quick access/removal of the pump). 

*Output side of pump: *
I will connect to the output side of the pump with a union connection, then a ball valve (to control flow) then to the bottom of the filter's 3/4" bulkhead. On the inside of the pipe I was thinking about connecting a tee to the bulkhead (maybe an inch above the bottom) and capping the ends. I will have holes drilled in the tee along the bottom and outward edges (but on a downward angle), so the water will be forcing the flow down and pushing the sand up. 
I was thinking about using some pea gravel (or possibly a coarser grade?) at the bottom around the Tee, then adding some Ehfi Substrat Pro, followed by 'X' amount of pool sand.

Also, I'm wondering if I need to add airline, say to the middle/top half of the filter or if the flow of water will be enough o2 for the bacteria.

So... let's have it. Feedback/questions/answers? I would like to hear something now, BEFORE I build it, then later when it's too late!

Thanks All.

PS - this will be additional to the Eheim 2028 canister that I'm running.


----------



## skelator (Mar 27, 2012)

sounds well thought out. i made something similar but without all the shutoffs and mines much lower flow. i made 2 actually. the bigger of the 2 is 4"x2' pvc. flat end cap on the bottom. the top has a adapter so i can use a threaded cap. i threaded mine with 1/4npt. my inlet is on the bottom aswell. the water much rise through the media to leave the connector i threaded into the top of the threaded cap. 

im just running 4 liters of denitrate in this one and the other one is basicly the same its just 3" pvc. that has 1 liter of denitrate and 1 1/3 liters of matrix. that extra inch in pipe makes alot of volume difference. my flow rate is pretty low i didnt size my pumps correctly. i didnt take the severity of the flow loss you get when the pump has to push up from the bottom of the tank. i could raise it up but i like it hidden. if this works out real good maybe ill up the pump size and just run the two inline with each other. 

i thought of using sand at first but i was worried it wouldnt flow well at all. i originally used aquarium gravel as media. it was used gravel and i think that screwed everything up as my nitrites and nitrates we off the chart in my effluent.

my small one only gets about 7.5gph i gotta tweek the tubing it needs to be changed. the bigger one isnt much better its only 10gph.


----------

