...... most common, but not the only, causes of necrotic leaf tips and margins are too much water and too little air in the root zone and a high level of dissolved solids (mineral salts from fertilizer solutions and tapwater). Very often the two work together to do their mischief and defeat your purpose.

Al

Thanks for the answer! I shall try to repot it, water it less often, and avoid tap water (which I don't often use anyways).

Know anyone with a reverse osmosis filtration system?

Sometimes, making sure you have the basics covered (good soil, good light, good fertilizer supplementation program, .....) is the best move.

This might be helpful.

Al

I grow peace lilys in water. You will most likely have to keep brown leaves and tips trimmed from time to time regardless of how you grow them.

That's not true. My peace lily does not and has not had brown tips.