hello robin, yes it is still working got my nitrates down to 0 or close to it per my test kit, the plans to make one are easy, but depends on the size of your tank, readig your stats it says you have a 75 gal, you will need a phosban reactor, no-no3 media made by carib-sea (goggle it) easy to find and cheap, an mj1200 or 800 pump, 1/4" tubing and 1/4 tubing ball valve.
fill your reactor with the media from one sponge to the next, hook up the tubing to the inlet and outlet of reactor, you will need fittings for this, you can use 2 1/4"mnptx1/4" tubing jaco fitting, use clamps to hold them to the outlet and inlet, hook your mj pump to the inlet of the reactor and put pump in your sump, and start it up, for the first 7 days go a drop a second on the outlet, send it to a bucket if you can, check the outflow for nitrate and nitrite, after 7 days you will see its magic, then you can up the flow too 2 drops a second or 3, just be very carefull, if its running and it smells like rotten egg, disconect it and clean the reactor and start again, if everything goes right this thing will not need service for at least 18 months or so, any questions let me know
sana