DIY aquarium canister filter

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.

Step 1 Drilling holes

Keep in mind the drilling photo was from the old design but the process is the same.the pipe photo is the good design. From the bottom of the pipe just above the rubber end cap  drill a hole with a small bit in the center of where your male garden hose adapter will screw in. this will keep your spade bit centered. drill with your spade bit slowly so you don't throw shrapnel around your room.
you may need to smooth it out or slightly enlarge your hole with a bit like the one shown. I didnt make the hole too large. i wanted a good seal. I wrapped teflon tape around the adapter a few times then threaded it into the pipe with the cresent wrench. take your silicon and run a bead around the adapter on both the inside and the outside. i dont suggest smoothing with your finger like i attempted. its difficult to clean off your hands. let this silicon cure for the recomended 48 hours before filling the filter with water for best seal.

the filter baskets will sit just on top of the outlet tube. to keep them laying even i glued a small piece of PVC pipe opposite the outlet tube at the same height.

also youll need to drill through the top of your drain plug. this is so the water can flow into it.