Here's a table demonstrating the rates of removal of different elements from a recirculating solution.
View attachment 3997195
Nutrients brands with a high Calcium content for example will cause issues as it accumulates in the solution due to it's slow removal.
Peace
BL
So that's why I have never seen Ca deficiencies ever in DWC. Even 25 years ago when I only had a few tubs under my belt no problems like that ever came up. I did on occasion see Mg def and used to always dose lightly with Epsom salts to fix it. Even an old fart like me can learn something new every day.
Thanks.
@OldMedUser which nutrient brands/products have you used for your runs with no nutrient changes?
As mentioned above I use AN pH Perfect nutes and GOOD RO water. Must be below 20ppm in my books to rate as great. 20-50 decent and I just won't pay for anything over 50. Looking to get my own unit. So check what you get from the store or your machine to keep it low. Some guys have tap that goes up or over 400 and those ppms get left behind each time you add more crappy water until you're at 2000ppm and only 20 ppm is nutes. That's an exaggeration but that's what's going on when you use hard water to grow your plants. Builds up in plants grown in pots too and causes toxic salts buildup just like it does in hydro. If you must use hard water for whatever reason then keep track of how much water you are adding back in your top ups and change the nutes each time you've added back as much water as your rez holds. That's for hard water like 400-500 ppm. If your tap is around 200-300 then you could go 1 1/2 and if better than that then twice as much before a nute change before salts accumulation will start causing problems like lockouts and too high pH that just won't come down.
I use nothing but RO in my potted plants too and don't worry about runoff and never flush but just feed RO the last 2 or 3 weeks so they use up what's left.
In my albeit limited number of dwc grows (4 now..), I've had different experiences - I think as long as you're checking the water regularly and change the res before any problem gets out of hand, you don't really need to follow a strict schedule
I've been using Lucas with GH in dwc- first with the flora series (micro+bloom) and now I'm trying the flora nova bloom for the first time.
With the flora series, I was starting to see issues with what looked like nute lockout about 2-3 weeks in. This couldve been my fault, too, from just not dialing it in - but I think I did.
With the flora nova bloom, I haven't changed out the res fully once- all I've done is a half change. My plan was to go all the way to harvest without changing the res if it can make it
After 4 you're starting to get the hang of it. Feed the plants when they tell you they want more. If you're still a little nervous that you might wake up to a disaster then change more often but for sure anyone should be able to do the first 4 weeks from clone and not change. Just add small amounts of nutes to bump the ppm up as the plants get bigger and are eating more and believe me it will work just fine.
I gotta say I would ditch the GH stuff for a couple big reasons. 1) They have always been hypocrites claiming they make nutes for flowers and veggies only and bashing the hell out of AN making all sorts of outrageous claims about AN and frankly paying posters, (shills), to respond to every positive AN post with lies and false news. Remind you of anyone like say . . . The freaking orangutan running the US! lol
2) They were bought out by Scott's a couple years back. The producers of fine pot growing products like Miracle-Gro who are in bed with Mon$anto who has now merged with Bayer who's roots are deep in Hitler's Germany. They made the gas used to kill a few million Jews, Gays and anyone they didn't like.
3) They use the cheapest possible ingredients with shitty quality control so a fresh bottle of their 3-part may be twice as strong or twice as weak as the last one. Their higher end nutes are a bit better but look at who makes them and ask yourself if you want to give your money to Nazi bastards or a nice Canadian/US company like AN. Botanicare and Gavita got bought up by Scott's/Mon$atan/Bayer around the same time as GH. Coming to a walmart near you soon as pot is legal federally in the US!
I won't buy a lot of companies stuff because of their business practices like Coca-Cola, Heinz, McDonalds etc etc etc. I may not have much but I do have principles and a conscience.
If anyone wants links to some of my past grows including one where I grew two tubs side-by-side and never changed one just ask and I'll PM them to you so you can see what I'm talking about. They are on another site so I don't want t opost them here. I'm out of town in Kelowna now and for the next 3 weeks so only get on when I'm not dealing with family stuff so might take a day or two. Niece's wedding next Sat and my mom's 90th b-day the Sat after that.
Driving into the valley on this week to attend my #2 son's court appearance for theft under $5000 so may be wishing him well in his year long stay in the Grey-bar hotel. Not his first offense but what's a tweaker to do eh.
Good luck and good growing you guys!
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