All of my girls are in late stages of flowering. They are all in DWC 3.5 gal buckets and are massive so they drink alot of water daily. I am using botanicare pure blend pro and hydro guard, and I know you’re not supposed to add nutrients to the water you add daily as to not make the pmi to high. So my question is what about the hydro guard or the other line of botanicare products? I ordered most of their line for next grow prep. What is safe to do to the water you add daily to your DWC containers?
I think the problem with that size bucket is that the roots take up majority of the volume, so you really can’t put much in there that late to begin with. If you knew exactly how much water was remaining in the bucket, it’s tds, and how much room you had to add water, it wouldn’t be too difficult to balance ppm. Since you really don’t know, you may be better off just emptying res and filling with fresh solution.
As far as I’m concerned you can add nutes with every bucket top off if you feel like, as long as you are putting in your nutes in a ratio appropriate for the plant’s life cycle and are maintaining PPM where want it in the buckets. I personally add nutes every other day (I’m using 14 gallon totes). Here is my reasoning. I use a 14 day cycle for res changes, so every other Sunday, usually, I do a complete res change.
Day 1 - complete res change, set PPM based on where I think the plant should be (ex: 800 ppm)
Day 2 - top off with plain water, measure PPM and compare against Day 1. (ex: 650 ppm)
Day 3 - if difference between day 2 and day 1 PPM is over 200, I raise the nutes and top off with something like 1000 ppm. If there is no significant change, I just add water again. If it’s around 100-150 I add the same nutrient level I started with.
I repeat this process for the whole cycle, adding water or nutrient-laden water to set PPMs where I want them.
In 3.5 gallon buckets you probably should check them at lights on and lights off, IMHO. My last grow I did the entire thing in 3.5 gallon buckets and I had to do that in late flower. It consumed the entire bucket of water in a 24 hour period.