over fertilized or a deficiency? please help

I did a watering in the bloom room with Epsom salt 1 tsp per gallon in the water. Ppm was 600 in (250ppm hard water and RO mix with Epsom salt only no fertilizer) ph in 7 runoff ph 5.4 ppm 1700. Should I keep using plain water until the runoff ppm comes down? I see signs of magnesium deficiency, phosphorus and calcium deficiencies also. Please give advice
 
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