I'm Having similar issues with my PH . my mix is 50% coco, 25% Vermicompost, 25% Perlite. using DTE 4-4-4 and 4-8-4. Run off PH is reading 8+ I checked with both a meter and a chemical test kit. i wash about 1.5 gallons of 4.0 PH distilled water through a .25gallon pot with no change