Lol…not all nutrients use the 5.8 ph there others that use ph 6.1 - 6.8 …there soil out there out of the bag that has 5.8 ph and others that have 6.2 -6.4 … of course you would take a nutrient that feeds at 5.8 and match with soil , like FF … I amend my soil after each grow and use nutrients too… and testing run off only tells you what happen before , a true test would be a slurry , then you know what ph and ppms are at that time…