Recycled rockwool is only good for so long. but lavarock can be used forever. People recommend cleaning it because of bacteria or particulates, and you should. But realize that bacteria are good inherently, and unless you have a real problem with those types of pathogens in your system i.e. mold, plant disease, fungus, they are of no concern but augment the plants ability to break down and digest the nutrients, especially biological nitrate based.

Rockwool is a hard substance to clean out, and i recommend doing cleaning in a system within your system. Yes you heard me, I have a sump type scenario where I do transplants and its a controlled environment. The escape pipe to reservoir #1 is 1 inch under water surface, so it does not pick up surface particulates, and debris accumulates on bottom. I don't oxygenate this part of the system, because I do not want a lot of current as it stirs up the sediment. This acts as a filter, sump, res, mixing, testing, transplanting, and most importantly a primary ballast.

Heres pictures. I would clean the rockwool out of the Lavarock and throw it away. Get new rockwool, but its good to let it soak up and get some algae before using it, as this is promotes bacteria. I found in my trials that my bacteria enhanced (microbial) organic powdered soil fertilizer works good in combination with these layers of rockwool and lavarock, just as in soil.

If you don't want to do the process in a sump type environment I would buy a big 50 gallon rubbermaid bin, and do your recycling in there. Just fill with water and take the lavarock out a handfull at a time, you should be fine. Use a fishing net, like a 3" net for aquariums, and sift out the debris with that. I like keeping it all in the system cause the mess stays in there and not in the room. Just make sure that mess does'nt escape directly into system, or do the really messy stuff in bin, like involving massive amounts of soil, and then lavarock cleaning in sump...

hope that helps
AquaponicHerb Reviewed by AquaponicHerb on . "Suckit Bucket" DIY thread You will need: 1. Drill, 1" drill bit, 1/2" drill bit 2. 1/2" 1/2" stiff black water tubing, 1/2" 5/8" clear hose, and garden hose. 3. >370 gph pond pump, with at least 12 foot height torque-rating. The stronger the better. 4. 3" hydro net basket 5. 3" pvc pipe 6. 3" pvc pipe end piece 7. There are some other small fittings that I will describe later. 8. 5 gallon bucket Rating: 5