Red hot cookies (one plant grow)

The red hot cookies 1 plant mainline is really taking off now. I had a slight zinc or sulfar deficency cant really tell in the pic but it's there. All new growth was light green. I check my ppm and it was low for a plant at this stage so my feedings will have to be much heavier to avoid the issue. I think she's fixed now, cross my fingers!. I'm running promix bx which is considered a soiless medium and it's to be treated like hydroponics so I've been keeping my plants between 6.0 and 6.2 I'm thinking of dropping the ph to 5.8 next dose then bringing it back up to 6.0 (I've been running the soil for years so i know how to disl it in well). none the less the grows been super smooth minus the little difficency. There's always a simple fix for everything. I have no doult the plant will produce well. Cheers