Both of my ph pens are wrong and I'm not sure how long they have been wrong, they both were reading near each other so i thought they were good. I ordered a new pen and after calibrating it i found my res was 3.8-4.0 ph when i thought it was 5.8-6 ph.
I just corrected the ph in the res even tho this is the end of the grow I'm sure this had some negative side effects for my plants as i think this was going on for 2 weeks or so
I was wondering why i was needing so much ph down and why my tap was 8.4 when its suppose to be 7-7.5
I think I'm going to order that bluelab ph pen and some storage solution so i can be more on my game. i seem to only get 1 year out of the $9 amazon ph pens so maybe $90 on a 2 year bluelab pen is worth it??