Recently the leaves of my sword are getting brownish & "lacey."

The tank is 87f
55g
no carbon
7.0pH
soft (75ppm) water
15hrs of light daily
some laterite in the substrate.

I use seachem's Flourish about once a week.

I did have an overgrowth of hormwort that may have been blocking some of its light - but I just trimmed that back.



Any ideas or suggestions?

It's very hard to raise great plants at the temps that discus require, at least in my experience. You might want to try feeding them at the roots and perhaps a little CO2. I think it was indigo that mentioned the clay balls with fert in the middle. I use plant tabs on my swords along with dosing with PMDD for the rest of the plants; but, my temps are much lower than yours.
regards
mike

I agree, that high temperature could have something to do with it; but, first I would try to fertilize the roots of the plant with either Plant Tabs or the clay balls with imbedded fertilizer. Fertilizer in the water column doesn't do a whole lot for swords, they are heavy root feeders....... some mulm left around the roots is also beneficial. Secondly, swords like some hardness in their water, your water may be too soft for them, but try the root fertilizing first.