Planted Tank Guru
Join Date: Jul 2010
Location: British Columbia, Canada
Since it's going to be low-tech, I suggest going with the existing light fixture for now and see how it works out. Low/medium lighting for a planted discus tank may not be the primary concern to start out with, but rather which plants can do reasonably well at the higher discus temps.
There are many plants to try out in this environment - I've had very good luck with amazon swords, hygrophilas, ludwigias, jumbo grasses, anubias, java ferns, lotuses, rotalas, bacopas, even sags & vals. Crypts can also do well, after an acclimation period of a few weeks.
Hope this helps.