soil ph is erratic fox farm ocean forest : pro-mi...

Hello there. PH mal-adjustment with, what looks like, a P/Cal deficiency. I also used Ocean Forest in my first grow because the pre-nutrient amended soil was attractive to me, but it kind of hurt more then it helped. Same as you, I ran into almost constant pH problems when using OC and it frustrated me endlessly (ended up using a neutral soil for the last 2 gallons for last pot up). Good news, I wouldn't panic over this too much. Changes need to made, probably some trial and error, but they will come back. Red/purple stems can be a symptom of P deficiency but I see your night temps are around 19 degrees Celsius and could this can also change the colors of your stems, laterals and leaf veins. Copper spotting does not look like splash back to me at all. I feel you're looking at a phosphorous and calcium deficiency. The uptake of these nutrients is optimal at 6.2 and with the current swings in your pH (and also work in conjunction with one another), I don't think the plant is taking much of it up. You can give it as much as you'd like, but she just may not be having it. Suggested solution: (Same thing I did to mitigate and remedy the same symptoms) Next feed (or two) I would simply "flush through" a good amount of pH balanced water @ 6.2-6.4. I would not recommend over-compensating and feeding anything about 6.6 as this may fix one problem while creating another (possible lockout of other essential nutrients). In these "flush throughs" I add my phosphorus blooming supplement with cal/mag (Usually 3/4 dose. Trust your gut, though). This way, you can properly flush out excess salts/nutrients/developing pathogens while not starving her of the P and Cal she desperately wants right now. After a couple consecutive flush throughs, you should notice the pH start to balance itself out. When you return to normal feeding (if pH is back in order) I would also suggest watching how much Nitrogen supplementation you give the ladies. Micro nutrients that work along side Nitrogen, like zinc, copper and iron, can interrupt the uptake of P and Cal/Sulfur and keep the soil mal-adjusted (uptake of these nutrients is around 5.5-5.7). OC medium is hard to gauge when it comes to Nitrogen. It's highly amended with these macro/micro nutrients and can certainly cause trouble. There are no hard answers to this question, but rather a roadmap to possible remedies over time. Your girls will be just fine. Just need a little tweaking!👍 I hope this helped my friend. If this is the answer you're looking for there is no need to "pick" it. Remove the question and keep it for another day😉 (Weird how there's a time frame limitation to questions...I don't understand why). Cheers and good luck, no matter what course of action you take!!✊