Hey dark devil
Just tuning in here. I was looking through your grow I'm kind of interested in that Pineapple Express. That's one of my favorite photos strains and I wouldn't mind trying it in an auto.
So that one seedling you were looking at I'd say that was more of an effect of a fluctuation in pH. It's kind of tough starting out when you're just wandering around this seedlings you're going to have some of that sometimes.
I take it you calibrate your pH meter twice at pH 7 and 4 or 7 and 10?
When you flush a plant in Coco you don't need to pH adjust your water going in, in fact all you really want to do is flush all the salt out of the Coco. The only reason to adjust the pH would be to try and get the plant to up take some of those salts and you don't want that so just flush with straight tap-water.
That assumes your tap water is good? Have you ever measured your background total dissolved solids?
You're going to want to start watering to run off soon, that is if your plants grow nice and quick. At any rate you won't be able to keep those bags down in those trays that you have in your tent.
If you could get a hold of some old charcoal grills or something those kind of things are usually laying around people's backyard in the states. They work well. I actually have a couple racks that I saved out of my last old non-working oven that I used to hold my plants up above their trays.
Once they get big enough I don't mind just picking them up and taking them out of the tent to water.
That's my watering station outside my tent it has an oven rack on top of about 12 or 15 gallon plastic bin.