High Times had an article about a similar system last fall, can't remember exactly when. Buckets connected to a small res. with a float valve that was connected to a large res. that was regulated by the float valve in the small res. A swamp cooler float valve worked for me. My copy of the system added a small, very small pump to move water from one bucket to the others, I used a small aquarium pump. I figured I didn't need to move the water quickly, just enough to keep a uniform PH. I also added a ball valve between the small res. and the growing buckets to shut of the flow when I changed water. Rather than putting the buckets in line I made a small manifold out of pvc. Made it easier to add or delete buckets if necessary. To this I attached a dead end hose with a ball valve to attach a pump to either fill or empty the buckets, but replacing water was more simple just pouring it into the small res. after everything necessary was added and PH checked. As the large res. only had a small line going to the small res. water dumped into the small res. got to the grow buckets quicker due to the larger size of hose interconnecting them. I also had a small aquarium airstone in each bucket. For a stone cold or was that cold stoned beginner trying all three, HID, LED, and inductive types of lights, it worked, quite well I thought, but having nothing to compare it with thats just my opinion.