Any ppm over 800 seems excessive to me soil or hydro? Running hydro myself, my ppm rarely ever exceed 500 ppm....on any strain I've run over the years. I don't feel the need to push my plants to its limits or until the tips burn though.
When during one of my early dwc runs, I was at around 1200ppm tap water was coming in around 400ppm out the tap
So I fed one cotton candy more than the other
in the end it took around 3000ppm before the plant burnt and then it was just the tips of the buds bleaching
So I don`t know what to say, obviously there is a max and a ideal where feeding more will get you more but is not worth it and then over that you start to kill the plant
but 800ppm is what I`d feed at the end of veg or early flower or going into the end of flower
and when running plants outside I noticed the ones I was light feeding were not getting as big as the ones getting the old dwc 1600 to 2000ppm res dumped on them, also the plants getting a weak bio bizz feed did not taste as good as the ones getting higher ppms
Not saying your not maxing out your set up @800ppm but I just know that low level of feeding would never work for me
but it could be down to a lot of the bullshit that`s in our tap water
but I`ve never seen a plant in bloom get burn under 1800 normally have to push them way over 2200ppm to get any burn on them
but younger plants in veg, yeah ok sometimes 1200ppm or over will burn them when there small and under 5 nodes, but normally feed 800ppm or so in veg don`t need to go wasting the expensive chemicals, lol
and I`ve run a flood and drain @ 1800ppm going from 1400 upto 2000 depending on the week, anyway had some plants get seedy and had seeds popping in the clay pebbles and growing right out of the flood table
let a few go till they had 2 leafs on them and they seemed fine not saying they would not have gone toxic but I do think what`s already in the water and what your adding to it matters
I mean 200 to 600ppm or some peoples feeds is boosters and zymes and other such stuff that don`t even really count towards it really