right i am using an iws system and have been running it with coco and clay pebs at abot 50/50 and now wanting to run it with just rock wool and clay pebs to cut down on mess and pest ect... but is there any thing i need to no do i just run it the same as i do with coco i no i will have to feed it a lot more but do i have to change the ph and ec at all?? and is there any thing i should look out for? i have used rock wool before in the eco grow system mark 1. but thanks for any help guys
well, you will have to test it...the water will probably run through the clay pebbles and dry out faster than the coco mix as far as changing ph and ec, clay pebbles should be fine. make sure they are clean. i have heard of people soaking clay pebbles for 24-72 hours in 4.0-5.5 ph water (much like you soak rockwool for 24 hours before use). i did that myself the last few times i used clay pebbles and did not have any ph swings, but i was in dwc those times, so water didn't hit them that much.
I veg my newly rooted clones on a flood table with a layer of pebbles for the roots to grow into and the clones are in rockwool cubes sitting on top of the pebbles. Works like a hot damn for me.