Ph down is actually easy to get and cheap, so well worth the minimal investment. I bought my bottle I think for 6 quid from a local hydroponics guy.

Plants look great- not stretched out considering growing on natural sunlight in north uk, nodes look close together.
I am new to this myself, so wait for advice on the holes and bites on the leaves.

Goodluck. I am interested to see how you're doing. I wanted to grow outdoor but sun so shitty here in the uk, I switched to indoor.