Lol just being grumpy
Wasn't sure if any of the people he replied to would still be floating around even lol
I've been considering going to a top up plan rather than complete change out.
I'm not sure id want to fill with RO and add nutes to make up EC though, I know a lot of the time those need to be in particular order and that might risk lockout.
I like to mix in my nutes in a separate storage barrel at an elevated hight, then I can dump it into my system all at once with gravity, or I have a float valve it can slowly drip fill my res as the plants drink.
I've done at least 50 tub DWC grows since 2001 before even Ed Rosenthal thought it was possible and now it's commonplace. I wrote to him when he had his Ask Ed column in Cannabis Culture magazine and he said he didn't think it would work. Calls himself a pot expert. lol I was the Admin at the CC forums when it shut down suddenly two years ago next month. Went by LabRat.
I never saw any problems adding small amounts of concentrated nutes directly to my tubs. I just suck up what I think I need with a syringe and slowly feed it into the tub. I'd add each separately and let the bubbles mix it while I got the next bit. Before the pH perfect nutes I'd drop in 5 or 6 drops of 96% H2SO4, (conc, sulphuric acid) to lower the pH. It would climb to 6.3 and I'd knock it back to 5.5 or so with the acid. Was so regular I'd only check the pH every 3 or 4 top-ups. I don't fret about stuff too much. I grew my first buds back in 1978 then on and off over the years until 20 years ago when I moved to northern Alberta with 6 hash plant clones and have been growing steady ever since.
My thing now is more CBD and indica strains plus getting into breeding more than just pollen chucking. Going to be using STS to make fem seeds and want to have good strain of fem autos for growing outside next year. Too far north for regular photo plants. I'm just using ProMix HP with hydro nutes and lots of pots to experiment and grow lots of smaller plants so I can search for the right phenos to breed with. May get back into DWC down the road.
I checked out your grow journal and pretty sweet! I think rather than chunk out that concrete to get more room I would have framed out a room in the corner there. A few 2x4s and some osb board and Bob's your uncle. My basement grow room is a 7x9x6.5'h cold storage room the previous owner had built. I still plan to add an 8x4 grow space to it and have a spare bedroom upstairs for vegging plants. That and the cheap price for 7.5 acres with a winterized 1990 16x80' mobile home with huge connected, heated and well insulated workshop sold me right away. Middle of nowhere but right on a 2 lane highway with 10 miles to a small town. Got my own mancave with all the toys I'll ever need.
I'm building my own RO system as the store bought don't have what I wanted. Our water comes from a dugout on the property so needed UV and extra filtration. $550 for everything but we buy 5 jugs of RO/week for $18 so it will pay for itself in 5 or 6 months and no more hauling heavy jugs out of the store then into the house.
I laid the things out two different ways to make it fit in the corner where the water distiller is. Going to re&re it and should be able to sell it for the $500 at least. Same modle used from the store goes for $1500 and was $3000 new. Polar Bear distiller with 10USG storage tank. Feed to the kitchen sink too. I'll have a line to the grow room right after the RO filter, a 2nd line after the last carbon filter to get low ppm water for the coffee maker and then it goes thru a calcite filter to add minerals for drinking and cooking water. 150gal/day like yours. Going to use the old brine tank from the softener unit for storage in the grow room. 150L and I'll have an airstone in there so lots of O2 for the plants. Filtered down to 0.5 micron.
Just pigged out on turkey with all the trimmings so time for a bowl and maybe a small micro-dose of 'shrooms.