I apologize beforehand for the glacial pace I do all my projects at - kids, the house, work, life, etc. have a way of getting in the way of our hobbies.
Anyway, I recently purchased a Fluval Spec V (haven't set it up yet) and read that one of the issues it has is its inability to suck up and filter mulm collecting on the substrate. Inspired by The Big Buddha and others building a Reverse Flow Underground Filter in this thread...
I decided to start building my own.
Playing around in the local hardware store (and in my basement), I discovered two things:
1. 1/2" ID, 3/4" OD vinyl tubing slides somewhat tight over the Spec's outlet nozzle once the flow director is removed.
2. That same vinyl tubing slides nice and snug into the socket of 1/2" CPVC fittings.
So I picked up the following materials:
4 - 1/2" CPVC Elbows
3 - 1/2" CPVC Tees
1 - 1/2" CPVC Street Elbow
1/2" CPVC pipe
1/2" ID, 3/4" OD Vinyl tubing (short length)
So, the interior layout of the Spec V is nominally 6"W x 17"L. I wanted to set up a manifold that would have 3 long runs parallel to the back of the tank, all connected in a loop. To keep the "sphere of influence" of each run equal, measuring along the centerline of each pipe, I wanted the loop to be 4"W x 15"L - this makes that so-called "sphere of influence" extend approximately 1" from the pipe centerline in all directions.
I also decided that I wanted to have a "hard-piped" riser from the filter manifold to the outlet nozzle, connected by a short section of vinyl tubing serving as a Fernco coupling. The nozzle's centerline is approximately 9.25" from bottom of tank.
So, I cut the following lengths of pipe:
2 lengths of 14-1/8" to serve as the "longer" front runs
1 length of 12-5/8" to serve as the rear run that the riser will rise from
1 length of 8" to serve as the riser
4 lengths of 1-1/8" to serve as short runs between the long runs - this gives just enough room between fittings to drill an outlet hole
Here's all the parts cut and lined up
Here's a mock setup of the RFUG (note that the street elbow is connected directly to the riser tee, saving me from cutting a piece of CPVC. The tubing will be cut to size prior to installation.
I still have to figure out how many outlet holes to make and what diameter [any suggestions?]. I plan to array them in a "zigzag" pattern within the two parralel "box loops" of the system. I will also drill outlets on the exterior of the entire loop to help clean and oxygenate between the system and the tank walls/.