If im not mistaken RO water should be near 0 ppm and 500 sounds way too high for spring water, stick with RO water and next feed do what i posted above, need a bottle calmag too with RO
RO 100 or less ppm is safe. The spring water has quite a few minerals but its ph seems normal.
As for calcium and magnesium my advance nutrients seem to hold plenty of those. I can add calmag to it though I have a bottle left over from my tomato crop. Btw my tomatoes came out huge for an indoor grow. I wish the weed was easy as that my tomatoes stem and leaves were a nice green then when the tomatoes fruited, they started with nice greens into yellow and red.
I will water and do a very very little feeding tomorrow and add calmag supplement just to see. Today the plants havent seemed to grow any more then visually what I saw yesterday
My new critical purple and tangerine dream seeds have all cracked this morning and I feel will sprout later this evening.. those are all autoflowers so it will be interesting to see how they compare to the blueberry that's having semi issues.
My cotelydons on the blueberries are still a healthy green, so I presume theres still a bit of food in there til they turn yellow and die.
I think I'm gonna pot my tangerine dream and critical purple into 3 gallon containers right away after they sprouted out of jiffy pellets I dont want them to hermie out on me.
But my blueberries once I find the momma I will clone her while giving her extra veg time in a finishing 7 gallon pot, I will be going from the jiffy pots to 3 gallon to 5 gallon then 7 gallon with the momma on blueberry