NO extra work...rez change every 7-10 days is great, as long as you keep rez topped off with ph 5.8 water. I personally have not had the nightmare's that "respected" friends here have had with rockwool. If you follow a regimen and keep everything "shipshape" so to speak...I don't think you will experience problem's...that's just my opinion.

I only use rockwool in 2 ways. In DWC it worked OK, and OK in dutch leach trays...but I grew in dutch leach trays without it and got the same results. I don't see the need that justifies the expense of 4" blocks. I use small pieces of r'wool and starter cubes for cloning, but I prefer straight hydroton. It is reusable...over and over. You just wash it with Flora-Kleen at end of each grow (soak at least 24hrs) and throw it in the ready bin. peace

Again. the best thing I ever did to universalize my growing...was to buy a 3.5"holesaw. for 3.75" netpots. I don't worry about the netpot holding plant up...although it does a decent job. I know going in that I will have to support the plant after it get's big.

As far as multi-dwc system...I am almost to the point where I may concede that I need an injection molded rez to pull off my ideas. peace. I will keep you all posted.