NotAquaMan
In Bloom
Yeah definately different. Pure hydro is faster than flood and drain but both have thier benefits. I would say the fastest possible growth rates come from aeroponics but the margins for error is also the greatest.Definitely. I don't have nearly as much experience as you (or any of the hydro growers I've met), so I'm all ears. I have found that even though both classified as Hydro and similar concepts, F&D and RDWC run quite differently in my limited experience.
I don't do full res changes, I just top off. So basically if I have a 20 gal res, and it goes down to 10 gal, then I will add back 10 gal worth of water and the same strength nutes for whatever growth stage I'm targeting. The EI sounds like something I'd like to know more about. I am always about continual improvement.
Top ups are not bad. A lot depends on the total volume of water you are working with. The larger the more stable and longer before you run into a ratio imbalance and lockout. It's absolutely possible in the right circumstances to not have to change the water for an entire grow. Not something I would recommend but it can be done. I generally only do 25% water changes weekly until flip which is about 3 weeks veg then then up to 50% weekly depending on my shift in my daily ppm.