Sorry if this has been asked before - i searched, and searched and found nothing. I am running 400w-600w 5 gal DWC lucas formula using the GH PH test kit because i broke my ph meter a month ago. I am having a zinc deficiency on my bubba kush 4 weeks in flowering and am pretty sure its because of my ph being too high, even though it looks good on my ph test kit. Im wondering if the reddish tinge to my res could be affecting color outcome of my ph test kit? I usually PH water then top off, but lately when i do it shows my ph really low after dding nutes.. When i add nutes to my 7.0 ph tap water (after 24 hrs) without adding ph down the tester shows below 5.5. And no matter how much ph up i add it just doesnt want to rise.. Not sure if the GH ph up is weak, the GH micro and bloom are buffering my ph too low, my ph test reading wrong, or lack of macro nutes? All i know is ive had the test color close to 5.8 lately and am still getting zinc deficiency. Thanks for any input.. p.s. already ordered a new ph meter but it wont be here until next wednesday probably..