Scrogdawg
Well-Known Member
I hear you on the big amount of nutes needed for 40 gal, I'm doing 25 at change time and adding 5 more mid week, and from this last change it will probably be 7 or 8 mid week because she was about to start sucking air!
If your running a tea and something like Z7, you can go longer but it makes it tough to figure out what is being used by the plant and what is lacking until it shows up on the leaves.
I've heard a lot of people say that OTM. I run 17-20 days between res changes. I use 20 gallons at change and 15 gallons top up between changes. I mix between 1.25-1.44 EC in the initial change and in the top up water. As I think your aware I run a GrowBoss monitor and am able to check many times a day. My PH, PPM's and EC don't barely twitch during a water cycle. At about 17-20 days my PH will start drifting quickly and that tells me its time for a res change. No harm to the plants and not necessary to wait for the plants to be affected.
Now the trick to being able to do this is to know what the max rate the plants will feed and drink at so your water consumption and nutrient consumption never change when you add your top up water. Balanced, water and nutes in...water and nutes out. The max rate, you find out early in veg by increasing the nutes till you poison the plant then back off to the previous recipe.
Sounds a little daunting but its simple and works really really well, and your always feeding to their max. I've never seen any adverse effects using this method.