here is an easy way to find out if u are using too little or too much ppms for your plants. first you put the water in your res (this is only for hydro) then u nute it to say 900 ppm, come back the next day. if the water has gone down like 2 inches it means the plants drank 2 inches of water. if the ppm is still 900 after they drank the water, it means the plants are drinking the same amount of water as they are the nutes and you have found thier optimal feeding range for that time in thier lives
now if they drank 2 inches of water and the ppm went down to like 700 then you know the plants are drinkin more nutes than water and you need to add some nutes.
if the ppm is higher after they drink water it means they need less nutes and are trying to extract just water and leaving behind the nutes, and you better fix it before they begin to burn
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