got you, thnaks, like your coke bottle experience haha.
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Yeah, thats probalby really the biggest issue with perlite, when it becomes top heavy, no good.
I do scrog mainly, this counter the problem a bit, also never used 100%, more 50/50 with coco.
What i do like about perlite, its nicely neutral and so cheap no recycling needed.
Without medium is the best, especially in your scale.
I failled trying DWC, nothing for my enviroment.
Saw a huge local tomato producer greenhouse who is using tons of cogr slabs.
Theyre really huge, using a own geyser for producing electricity and heating the greenhouses.
So your mentioned slabs could be one good way i large scale... my TV told me,lol.