I guess that's what they say in The Matrix. Lets take a 500 mg dose of reality pill.
Here is Blyxa planted on the same day that the tank was flooded. The plants were purchased from Malaysia, and therefore had travelled 8000 miles 4th class, so they were in the post about 7 days and were not happy campers. The water is murky in this shot but you can still make out the plants. By the way, the GH was at least 25 German hardness degrees (approx 450ppm.)
Here are those same plants almost exactly 8 weeks later. Think about it: How could a change of water parameters be an issue if you change your water every week without the plants melting? If anything, they do better after a water parameter change.
You can see a couple more shots of these in the thread
Blyxa Japonica Flowers Underwater
Picky? Absolutely not. The problems with Blyxa always start in the mind of the aquarist. If Blyxa is picky it's because it does not tolerate CO2 carelessness. Instead of blaming the plant, only try to realize the truth and blame yourself for poor execution of flow/CO2. It's highly likely that if Blyxa melts in your tank then it is a warning that more CO2 related problems are lying in wait just around the corner, so you have to recognize this and stop looking under stones.
Good CO2, NPK+Traces as well as good flow/distribution are how you convince Blyxa to not melt, and really, that's true of all plants. I can only think of about 5-10 truly picky plants. None of them are called Blyxa. Like all the other weeds, once you allow this plant to bulk up on CO2 it becomes obnoxious and unstoppable. Melting plants ALWAYS means poor CO2 and can never mean anything else. Once you accept this and internalize the concept you'll be on the path to success.
Cheers,