Everything keeps melting
I'm not sure if i should put this in this forum or the nano tank forum. Last summer I started my first 10g low tech planted tank. In it I have a thin layer of laterite under a layer of black sand and a light that said it was good for plants. I cant remember what kind of light it is. I also have fake driftwood and a rock. However, every time I tried to add plants they would turn brown and melt within a week. I have tried a peacock fern, Christmas moss, "beta bulbs" (assorted bulbs from Walmart), and a marimo ball. Algae won't even grow in this tank. After months of trying to get plants to survive I gave up and the tank sat for about a year.
I finally have some extra money to try again and I want to turn it into a planted shrimp tank. I did a massive water change about 75% and have dwarf water lettuce, java moss, and Marsilea quadrifolia coming sometime next week. My temp is 72 F, pH 7.5, GH is less than 100 ppm. Is there anything that stands out that would cause these new plants to die? The only thing different about the water is the temperature is lower this time. Could that be enough to cause everything to die last time? I'm really worried everything is just going to end up dying again. Any tips or suggestions would be greatly appreciated.