I'm not using an airstone, and I'me getting some kind of weird slime on my roots, fletch suggested I put an airstone in... so it might be mandatory?
I guess not really if youre using H2O2 but I dont know
no filters, fletch said earlier hes using a fnely woven bag made for putting around your pump that dosnt alow small particals to get in there... I asked for one of these at my local hydroponic store and the lady thought I was nuts... and it took her a half houre to tell me she didnt have it. so I'm using 2 of thoes finly woven nets used for pool vacumes. more expensive hydroponic water pumps have a filter over the intake so this isn't necisary, the bag isnt neccisary eaither, but it sure helps
