I looked carefully at the UC and at several other designs- and then built my own. Things I liked about the UC- and incorporated; continuous recirculation of water, 'epi-center' concept, large water capacity, relatively small parts count, both in terms of total parts needed and number of different parts required; this simplifies keeping an inventory of spares. I did not like the lack of a 'tail' bucket, where water from several rows combines before being sent back to the epi-center; I find this to be the best place to add nutes and the like as it has a chance to mix and dilute both here and in the head bucket before it ever sees any roots. Also, a tail bucket tends to accumulate the crud or debris in the system, making it easy to spot and remove. Lastly, this is where I place my pump, with the filter still in place, with a line from it to the epi-center. For a 24 site system made of 5 gallon buckets, I've successfully used pumps as small as 250gph and as big as 650. Ironically, the smaller ones seem to work better. I used 1" bulkheads from n-g-w, as the ones from C.A.P. are made from poor molds and leak. I used 1" flexible tubing to connect everything, and it has the advantage of being much more flexible than PVC piping, and much easier to adjust, set up, take down, move or alter. Parts list and approximate costs for 24 site system: 26 5 gallon buckets- free, I just asked around at local restaurants! Only take ones that had food in them, not nasty chemicals, or buy for about $6.00 each; get green or black- or buy some paint to block light... 1 250gph submersible pump, $30.00 or so 54 1" n-g-w bulkheads, I paid about $3.00 each in bulk 50' 1" i.d. tubing, $1.65 a foot 8 1" 90 elbows- shortens overall length of system to fit in light footprint, $2.50 ea. 2 1" tees, plumbed just upstream of tailbucket, so rows drain more slowly into tailbucket than headbucket can fill them, this helps maintain water levels, $2.75 ea. 100' airline tubing, $15.00 1 Eco plus 7 200 litres/min air pump, $120.00 or so 24 Eco plus medium airstones, $2.00 each in bulk Misc air fittings, $25.00 or so 1 Float valve for top off, $20.00 swamp cooler part Ballpark cost is well under $500.00 for a 24 site system that will fit nicely in an 8x8 space. If you want it to cover more area, just buy more 1" tubing and airline tubing. Costs not listed include instrumentation of your choice- Blu Lab's Guardian comes highly recommended but it's pricey- and cooling; 1/2hp chiller will be more than adequate, and you could get by with 1/3hp if you choose to insulate the buckets with foil covered bubblewrap. I run a big chiller to cool not just my RDWC, but also my rooms, so I just dropped a 15' length of 3/8" i.d. copper tubing ($25.00) all coiled up to fit in the headbucket, ran some hoses to my cold water and return manifolds and bam!- cool running water, oxygenated, nicely mixed in each bucket due to the bubbling effect of the airstones. Operating capacity will be about 100 gallons of water. This design can of course be modified endlessly, to accomodate bigger buckets, more or fewer buckets, various center-to-center measurements, different shapes, and it's nowhere near as much of a c*ck-s*cker to tear down, move, adjust or alter. Word to the wise; if you decide to run more buckets, I wouldn't try running more than 8 sites in a row, and I would definitely use a smaller water pump (250gph) rather than the big one you'll be tempted to try, otherwise water levels will vary too much from one end of the row to the other.