Oceanforest PH

I’ve done 3 grows with ocean forest, each one has had low ph issues. I’m growing autos, indoor 4x4 tent, 2 mars hydro tsl2000 lights, 6 inch ac infinity, fabric pots and freshly purchased bags of recently arrived ocean forest. So this last grow had presumably good soil.

I’ve checked runoff about 4 weeks from sprout(the first decent watering) 1st grow , 2 were at 5.0 and 2 were at 5.1, second grow, 2 were 5.4 and 2 were 5.3, just checked my 3rd grow at day 20, ph was 5.0 on the only one I checked, I said fuck it after seeing that. At least 1 plant has been stunted in every grow(I got one that’s 2.5 inches and has stopped growing, ). 1 other is real small and probably stunted also. The remaining 2 look great. I do not over water, no big temp or humidity swings, I didnt get a chance to fertilize before the stunted ones appeared. Am I the only person to see this every grow? Fox Farm says ph buffered, but my plants dont seem to grow very well wih a PH of 5.0

Thanks for any input