Instructables
I've wanted to build this project for some time now. Finally had the time. I esentially made one and a half. The first filter leaked and had some design flaws. so mid way through I changed the whole design.
Disregard the threaded pipe cap and the rounded cap. those were from the original design.

You'll need:
8" of 4" diameter PVC pipe
1 - 4" diameter plug
1 - 4" diameter rubber end cap with hose clamp
2 - female garden hose repair ends
2 - 1/2" threaded valves
4 - 3/4" to 1/2" threaded plastic hose conections
1 - male garden hose threaded (2 pictured for old design)
3 - pvc grates about 1 1/2" tall
1 - 3/4' 90 degree corner tube(has hose ends)
some small hose clamps
PVC cleaner
PVC glue
teflon tape
aquarium silicon
20' - 3/4" tubing
5' - 1" tubing
3 small zip-ties
and of course a pump. mine was a 700gph in line pump

Filter media:
poly sponge(got one for car washing)
knee high stockings( cheap ones in those little plastic balls)
bio-balls

Tools:
Drill
small drill bit
7/8" spade bit
coping saw
utility knife
flat head screw driver
channel lock pliers
cresent wrench
needle nose pliers
tape measure
sanding block
scissors

I may have forgoten a few things and you may need to swap a few parts to fit your needs exactly. I hope I explain it well enough to be understood. Any comments feel free to post. also please rate!

make the pump PULL water in the top and out the bottom. do not plumb it to push water through. it builds to much pressure and WILL blow the plug out of the top. I found that out the hard way. thank God for those valves installed or it would have syphoned my whole tank onto the floor. instead i caught it quickly and only about a gallon spilled.


 
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So the biggest tip here is that the pump needs to suck from the fresh filtered side of the filter and pump up to the top? Check!

Thanks for the write up!

jlundquist (author)  yosemitesamiam1 month ago
Yes. This was a mistake I learned the hard way. Pushing water through causes too much resistance. I blew the filter open and spilled water everywhere.
I could see that happening! I'm really torn between building a filter or buying a cheap Chinese unit (under $50 with one pound of ceramic media, 40 bio balls, and a 265GPH pump)...the pump I have I believe is submersible only...that will be the deciding factor unfortunately. I've bookmarked this for future use though...much appreciated!
chevyguy1512 months ago

i'm having a heck of a time finding an in-line pump. where did you find yours at?

jlundquist (author)  chevyguy1512 months ago

I don't remember where I got it from but here is the same pump from a website. The pump is a Danner supreme mag drive. There are different gallon per hour options.

http://premiumaquatics.com/products/danner-magdri...

can we use a submersible pump?
I would assume so. make more space in the bottom of the canister, underneath the final filter basket and it should work.
royalspin1 year ago
All in all I like your design ,its really simple which is good.Some people get way overboard with they're life support creations and rely way too much on technology instead of basic biology.For those who don't know much about keeping fish,remember this one rule.The bigger the tank the more stable the system will be especially in a situation when you lose power often. Where I live we have too many power outages,so I have to keep that in mind when creating anything for life support which is one of the reasons I haven't got back into a marine setup since I moved here.In a marine system water chemistry ,temp,etc are critical.If you lose power or the ability to keep the water chemistry stable you can have a massive die off happen rapidly especially in smaller systems.As to your system -out of curiosity how was the flow through using the poly sponge vs.regular filter media ? I tried using something similar on a hanging filter one time and found that it clogged very quickly because its pretty much designed to hold water rather than let it flow through like say acrylic stuffing or filter wool etc.I designed something close to what you have there and used a bunch of net bags that you get when you buy things like onions or garlic.They're chemically inert, have tons of surface area for bacteria to grow and tend to catch the larger debris without clogging.I usually use the netting 1st, then a layer of landscaping gravel like the stuff you see in playgrounds mixed with a couple of tablespoons of carbon,then bio balls last.Anyways thumbs up on your creation.
jlundquist (author)  royalspin1 year ago
Thank you for the comment, sorry its taken 8 months to reply. yes the sponge was a bit of an issue. it did hold to much water. but it did collect ALOT of bio matter. I had to remove and clean it every 3 days or so.
TorBoy91 year ago
It is an interesting design, but I had to work to understand your build. There are differences between your initial build and the final build, but some of the instructions are not so clear. For example you used a "4" diameter rubber end cap with hose clamp", yet you state you need to drill the top cap for the intake hose. I am unfamiliar with a 4" diameter rubber end cap with hose clamp but it seems that it comes predrilled. Is drilling the top cap a detail from your initial build and not applicable to your final build?

The filter layers out of drain covers is quite nice, as is your zip tie pulls. I usually do not use carbon any more, opting for more biomedia instead. I suppose you could build your filter taller than 18", giving you more room for extra biomedia.

What happens to the filter when the power goes out? Does this filter flood your house? Is the 4" diameter rubber end cap with hose clamp really water tight?

Overall a good design. Is it still in use on your tank?
jlundquist (author)  TorBoy91 year ago
For starters thank you for the edits. I made a few quick changes. Took out the picture of the pvc end cap and the instructions to drill it. I guess I didn't preview very well.
When power was removed it held water tight. The filter is currently not in use. My Oscar died and I just haven't replaced him yet. When I replace him I plan on upgrading the hoses to pvc pipes. I got a kink in one of them occasionally. also I will be using a different form of physical media as suggested by another comment.
stitchiner1 year ago
that sponge u used is no good as you need open cell foam. ensure you can easily blow through it while against ur lips. same goes for the tights (panty hose?) you can also try soaking each in water and blowing through again. if you cant then you are seriously reducing flow rate. for media bags i found voile is best, bunch at the ends and cable tie.
jlundquist (author)  stitchiner1 year ago
The Sponge did pose some problems, but the panty hose worked just fine. I'll have to try voile.