Yeah I have jbl aquabasis plant substrate underneath the sand. So far the HC is doing well and hasn't melted anymore. I tried to find some yeast around here at the supermarket and I can't seem to find any but hopefully they were just out and I can get some for my co2. I also now have some brown algae or diatoms due to the higher lighting lol. But hopefully the co2 can balance out the equation.
Good call for the co2.... Hc needs high light and if you have high light you should go ahead and add co2 and Ferts.... It's still picky though... It's one of those hit and miss type plants.... Just play around with it
All emersed-grown plants will melt when you put them into water. The only way to maybe, hopefully avoid it is to blast the tank with CO2, light, and ferts when you put the plants in. This will trigger such rapid new aquatic growth, they won't really be able to melt. You also need to break up your clumps more. Either plant it in very, very small clumps, or individual plants is best. That means one stem. Yes it is tedious as hell. Long tweezers help.