You got lucky in the fact it was a gradual degradation of their habitat, after your previous attempt it would be good to get all test kits and get an understanding of water chemistry
Add plants, a couple of fish and a bit of driftwood and wait for a week then check ph before adding anything else. Things will change as the tank cycles.
lol, thought you would have answered.
still a cushion star, get some variation from 4 to 7 legs
what colour is the top side?
how long has the weed been in there?