6.0 is not too acidic. It could be your lights. Or your feeding get a fertilizer with high phophrus max bloom or somethin like that. 8-34-8. It usually takes 8-10 weeks for flowering to end and for the pistils and hairs turn amberer. Wait longer thll get bigger.
the chart i have says plants in soil wont take up phosphorus if the ph is above 7.5 and below 6.5. im using a 150w hps in a 3 sq ft area and my nute is 10-54-10. i know it will get bigger later but its so small compare to my last grow and other people grow at 5 weeks. what about flushing will there be any negative effects flushin this late in flower?