This is an organic.I feed canna cal+mag full with ...

Hey there @PitchDope! I am noticing your bottom right plant appear suffering from a slight case of Interveinal Chlorosis(yellowing) - Primarily this is caused by a Nitrogen or Magnesium Deficiency. To best diagnose your plant we will need to look at exactly how that Chlorosis is spreading on the leaf (your 1st image is the closest to real color so i'm using this). If the yellowing is 'bleeding' from the edges of the tips going inward (this is what it looks like) the you have the starting of a magnesium deficiency. If however the Chlorosis(yellowing) is all over the leaf and not focused on the edge then this is a N deficiency. Given the Chlorosis Bleeding effect I see in the first image I think its safe to say magnesium----- Your plant (backright?) with the dark brown necrosis(death) marks at first glance shows the signs of both Manganese and Phosphorus Deficiency however a Manganese deficiency is accompanies by a chlorosis on the same leaf so We can eliminate that leaving just a Phosphorus Deficiency.. The first thing I am thinking is that you are using RO water and the only the Suggest amount of Canna Cal+mag. However if you read the Canna Cal-Mag label it says to add cal-mag to your RO water to give it normal levels FIRST Then following the suggest feed schedule. This fix is simple - just add some more Canna Cal-Mag to make up for the RO water and fix the Magnesium deficiency at the same time then look to supplementing some more Phosphorous(P) 😎 If you have any more questions feel free to ask them at any time!