DWC Biscotti Auto in Small Space (40*40)

Setup is pretty much following this DWC guide: https://old.reddit.com/r/Autoflowers/wiki/guides/dwc. I am using reverse osmosis to filter tank water. For light strength I will be using this PPFD table: https://www.led-pflanzenlampe.net/wp-content/uploads/2022/12/DLI-Tabelle.webp To determine the correct distance for my lamp, the manual shows dim and distance options on page 3: https://resources.cre.science/Datasheets/Bloomstar/fluxshield_habibi_150-de.pdf Started germination around 24th of December. Took a week for the seed to open, longest ever so far. Tap root is about .5 cm as of today (Jan 2nd). Will be transferring to DWC system in the next days. No added nutrients yet. Water is around 6.2pH and 0 ppm. Going to let the air pump run for a while and test again after adding first nutrients to see if I want to use any pH down.