I have a 14g cube tank with one of these in it. They definitely block the light over time, but I love everything about these plants, so what I've been doing is keeping them trimmed to about 5 lily pads, depending on size. I don't run co2, so my low lying plants are minimal and not spreading much - they probably still aren't getting enough light, but they are holding their own. I'm ok with that and I think, overall, it's working out for me. Maybe you can find the right balance for your tank of lily pads, to help your low lying plants, while still enjoying the full effect of the dwarf lily.