hi mate, try sticking your drop checker further down, maybe 2" from the substrate to see if the co2 is getting down to where you want it, flow certainly there bud, what's circulation like, is it getting all around? i'm sure you're pulling your hair out mate, are you still dosing liquid co2? maybe 5ml or double dose for a week to see if it improves, getting that magic balance is not easy, you're sooo close