DIY Pre filter for canisters, or power vac

[hmt321]

I have been trying to figure out a pre-filter that would be easy to clean out, also iy could be used as a filter on a power vac.

here is a picture

what you are looking at are two 4" - 2" pvc combinations (lowes aprox $8.00 each)

I have a short piece of 4" pvc joining them, between the top combo and the 4" pvc I have a "knock-out" that i cut a 3 3/8" hole in to receive a hommade filter sock.

this next shot is looking down from the top

the modified knock out is visable

Most filter socks that i found were larger than 3 15/16" (which is the max size for the 4" PVC) so i had to make one

what you are looking at is my 3" homemade filter sock.

I used a Seachem 180 micron filter bag 5" x 10" for the sock

for the ridged ring at the top i used a 3" thinwalled pvc drain plug (the kind that will fit inside 3" this walled drain pipe)

the Seachem bag fit very tight on the plug, i cut a 1/2" piece of 3" thinwalled PVC and siliconed it in place to retain the sock on the modified knockout, the rubber band acts as a gasket and gives it a tight fit.

To seal up the top and bottom of the 4" PVC combinations I used inspection plugs (about $6.00, lowes) the bottom could easily be permanently sealed with a cap, but the inspection plug allows more access.

I am going to use this one as a power vac, you can see a clamp that i screwed to the top lip of the 4" combo, i can just hook it to the top of the tank hood, or tank itself.

I will test it out then install one with a valve on either side to use as a pre-filter for my 125 gal tank (i have 2 ehiems 2028, and a fluval 405) on it.

I had it set up as a power vac

The gravel vac was attached to the top 2" inlet with about 8' of hose with a garden hose attachment. I had a Quiet-one pump attached to the lower 2" outlet and a return hose that went back into the tank. quiet-one pumps are not suited for this application because my manipulations of the return hose caused the impeller housing (attached to the 2" outlet) to come loose.
it worked good until the pump came apart. I will go and get another pump in a day or so.

also 180 micron is a little large, and the water got slightly cloudy, with a finer sock it should work just fine.

accessing the filter sock is very easy on this

if anyone knows where i can get a filter sock smaller than about 3.75" please let me know.

if anyone has any idea on improvements let me know.

 

[dawnmarie]

I like it. I built a power vac over the weekend and was left pondering a solution like yours. I'll be building one similar this week.

 

[Conner]

Very interesting. I built a diy canister filter (its over in the setup and filtration forum), and I was trying to figure out a way to drop a micron filter sock in it. I will have to see if I can do something like this. Thanks for the idea!

 

[hmt321]

glad you like it,

if we can find a stock filter sock that us under 3 15/16" then this will be even easer to build.

 

[Jgray152]

lol. so much for having a canister "FILTER".

 

[dawnmarie]

lol. so much for having a canister "FILTER".

How would this idea be different than using different grades of filter material in either a sump or canister, other than the obvious cost savings and ease of servicing ?
It seems as if this would be a simple, cost effective way to extend the service interval of your FX-5's

 

[Jgray152]

How would this idea be different than using different grades of filter material in either a sump or canister, other than the obvious cost savings and ease of servicing ?
It seems as if this would be a simple, cost effective way to extend the service interval of your FX-5's

Well, you pay for a canister filter which has 10ppi sponges all around the baskets to trap large debris.

You then add another filter before the fx5 which traps large and very fine particles which makes the sponges useless for mechanical filtration. Basically, the Fx5 turns into a large bio filter. The additional area for the bacteria will not make any positive difference in your tank.

 

[JakeH]

Well, you pay for a canister filter which has 10ppi sponges all around the baskets to trap large debris.

You then add another filter before the fx5 which traps large and very fine particles which makes the sponges useless for mechanical filtration. Basically, the Fx5 turns into a large bio filter. The additional area for the bacteria will not make any positive difference in your tank.

I've heard all the talk about FX-5's not needing pre-filters & I agree that they were designed for use w/out one (with the coarse foam you mentioned). I also agree that FX-5's already have plenty of bio area. However, I think your statement about the prefilter making it a giant bio filter is a bit extreme...
First, those 10ppi sponges are most certainly already housing BB & doing double-duty as bio/mech. So, I dont think the sock will increase or decrease the bio capacity significantly.
Second, if the filter sock were coarser than the 10ppi foams & easier to change, then it should increase the life of the FX-5 foams at least by a little bit. As an example, I just cut up an old Biomax bag from one of my AC HOB's & used it to screen leaves & moss from getting sucked into my PVC overflow. Now they arent clogging my sump inlet or decaying in the first chamber & I can remove the leaves just as easily as I feed the fish.

To summarize all that, I say use the sock pre-filter as a VERY coarse mechanical stage, just like the intake strainer that came with the FX-5. That thing is worthless anyway. Just turns the leaves sideways before sucking them up... Think of it as a flow-thru settling chamber. If the mesh sock is too fine, it will just put extra strain on the FX-5 & it may shorten the life. Just my opinion, though!

 

[dawnmarie]

That is where I was headed. If you use a 100 PPM sock this ought to extend service interval. There must be a reason the manufacturer(Fluval) gives flow rates with and without filter media, 607 Gph with and 925 Gph without. I'm not dissing an FX-5, I'm just trying to understand the concept. Does somebody want to explain to me the difference or correlation between PPI and PPM ?

 

[KaiserSousay]

Nice build, allot of original thought.
But for the money invested you could have simply bought a whole house water filter and had your choice of micron rated cartridges for use.