only way 350 hurt you in soil is during seedling stage and germ and germing the seeds, i run 250 until i get 3 sets of true leaves
once im at 4th set time to top and give the real deal water,mine is 315 from tap and my aquafier is a limestone base,in soil i dont feed anything up to about flower time and then if i feel like it i top dress and scratch in a dry amend every couple weeks if i remember to hahaha.
soil is a filter it can filter nuclear waste look at russia, look how mother nature has reclaimed many lost towns, houses grow right threw a trunk lid on a car haaha.
soil really doesnt require all the glory most claim ,let it do it thang ,if your looking at force feeding plants for that extra yield i guess maybe coco or water be better but a lot of nutes arent required and most kill the colony below