Gorilla Glue - First Ever Grow!

Week 5 of veg honestly do not have a clue how I’ve managed to get this far with her looking half happy have come across a few slight issues along the way but seems to have cleared up I think, ppms haven’t been reading what I exactly except feeding with 600ppms ph 5.5 all the time as it rises a few points I should be in the safe zone and the run off when measured is way lower (180ppms) and I’m sure my ec pen is fine so I’m so confused I don’t bother testing the ph run off as it fluctuates all the time aslong as it’s ideal what got put in I should be fine I heard i just done get why I can’t seem to get