i had the same problem! i used to run out of ph up before i ran out of tiger bloom.. the plants did fine,so your ok. thats just the way it is. i switched to general hydroponics and use just a bit of ph up now. but i grow ebb and flow. i don't know how your set up. but i'd say your good as long as you've got lots of ph adjuster
it drops it to like way more down than that i have to use like 8 quarter tsp's of ph juice. a drop of that stuff fixes other stuff tb and open ses and im dumping ph juice in by the spoonful. its what it says im looking to be reassured