I just realised I've got the exact same brand and size tank without the purple base
Sorry to hear about your plants. They were probably trying to adapt from being grown emersed previously and without cutting the melts and some carbon not all make it. I know it's easier to grow them that way and sell them as they are algae free but it's really a waste of money sometimes. There's also species of althernatera sold in fish shops that are non-aquatic and will do better outside in your garden.

Sorry to hear about your plants. They were probably trying to adapt from being grown emersed previously and without cutting the melts and some carbon not all make it. I know it's easier to grow them that way and sell them as they are algae free but it's really a waste of money sometimes. There's also species of althernatera sold in fish shops that are non-aquatic and will do better outside in your garden.