The number-one thing I wish I'd known was about removing potted plants from the rock wool. I had dwarf and giant hairgrasses (Eleocharis parvulus and E. montevidensis), watersprite (Ceratopteris thalictroides), and Alternanthera reineckii that were all bought in rock wool pots. The rock wool was ugly, but I didn't know it wasn't required. Over the last few weekends (thanks to this site), I've removed all the rock wool, spread the hairgrasses out into a couple of dozen plugs, planted the roots of the Ceratopteris more securely in the substrate, and discovered that the Alternanthera was actually a cluster of about eight plants, tightly rubber-banded together (no danged wonder it wasn't doing well!) Lighting and CO2 were, for me, sort of "Hmm!" issues - easy to find out about, easy to rectify. The rock wool issue was a real irritant, and its elimination has been a great improvement in my enjoyment of the plants. Good luck with the column!