PH drifting. Nute mixing.

Not really a problem but a question that has been bothering me for a while. So I'm using Heavy16 nutrients. When I mix a batch I make sure the PH is between 5.8 and 6.2. If I mix a batch and I read the PH as 5.9. I'll water. Sometime I get distracted though and don't water till a few hours later. If I wait a few hours the PH will remain at 5.9. But if I wait overnight the PH will drift up alot. Sometimes to like 7. I'm just wondering this same PH drift occurs IN the soil after I water the plants? Or do the other nutrients and things in the soil buffer the PH from large swings and nutrient lockout.

I was wondering the same thing.

Its probably the chlorine cooking off out of your water. Chlorine is an acidic oxide and will evaporate out of your tap water. I used to have the same trouble. Let your water sit out before using. Use a trash can or something, fill it, let it set for a couple days or use air stones to speed up the process. Then use. You will get no more drift.