So WTF lol I have to add ph down on a daily basis and lots lol. When I do a res change which is every 7-8 days I have to add 100 ml per 100 L just to get it to below 7 and then its a real bitch to keep it there. Thats been my biggest issue to date! I would love to get RO but its complicated lol. No plumbimg in the shed! Like I even went as far to start using sulphiuric acid to be able to up the concentration I throw in. I also use Sensi ph and it will feed plants anywere between 5.5 & 8 I believe without lockout. But never had slime lol just something else to look forward to huh lol. Actually I'm on my way out to throw some acid in now as I pull on the rubber gloves lol.