The plants are still really young so you do not want to go crazy with the PPMs and those number should be ok unless your starting water PPMs are high? The other thing to consider is the balance of nutrients in the res. Are you following the vendors recommendations? By that I mean if you are supposed to add 10ml per gallon of Part A and Part B and 5ml of additive X When you calculate 40% strength You need 4ml of A&B and 2ml of X to keep it in balance.......... does that make sense? This is all about Liebig's Law of the Minimums. It states that uptake of the nutrients present to the plant are limited by the lowest nutrient present. This is a visual of that Idea. Even though many nutrients rise above the level of the lowest one they are just wasted since the plant cannot use them. In this picture Se is the limiting nutrient:
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This explains why we need to change the nutrients in the reservoir weekly because we have no way of knowing what the plant has been taking in all week and our balance might look like this picture. We want all of them to be level or in balance. This is also the reason why I recommend growers to use One nutrient brand only and to use all of their products. They are designed to work together in balance.
