one fan leaf curling/twisting up and yellow on tip

Title says it all

I have 3 plants 2 weeks old that seem to be growing well. Cfls are a few inches away yatty yatta. Ffof/perlite 80/20 no nutes. One is in a solo cup and is short (2-3 inches out of soil but its newest sets of leaves are growing somewhat sideways, purple stem) the other two are in wider, slightly deeper plastic pots. one seems to be doing well but the stem is still purple and lastly my largest plant. It has a healthy green stem but one fan leaf twists inwards and up a noticeable amount. Also, I'm not to sure what it is called, but the 2 tiny not fan leaves underneath the fan leaves, one of them is turning yellow at its tip! This plant is about 4 inches out of the soil and looks great aside from that. I water lightly around on the outside rims of the pot. No nutrients added and don't plan on it for until several weeks after transplant (which I plan on doing sometime this week once I address this problem)
24/0 plan on switching to 18/6

I wish I could upload pictures but have no computer at the moment.

Could it be my tap water. I have no ph test and heard they are pricey so I haven't gotten one.

Could my lights be to close or light leak? I'm ruling to close out because my 5 23s are spaced and a decent distance and the yellowing is on the bottom which would bring me to llight leak could that bottom little niglet leaf not be getting enough life? I rotate my plants positions every few days.

Thanks aton!

read the affect of high ph. purple stems . high ph.

But the yellow as well? nd curling? And why would 2 be purple and one green

Does the plant look healthy overall? I get yellowing at the bottom of my plants (fan leaves only) and just write it off as nutrients going to the top of the plant for new growth and the old stuff dying off. If you're serious about doing this, a PH tester is very cheap and will help a ton. This is the PH tester I use here. I used to use the color changing drops but imo those are pretty crappy.