Crypt melt is not what the forum says it is
Mention Cryptocoryne melt anywhere and you will get the same litany: pH swing, temperature swing, "unstable parameters." All three are repeated with total confidence and almost no experiments attached. I have melted and regrown the same C. wendtii 'Brown' four separate times on purpose — twice in a 60P, twice in a 20-long — and what actually triggered each melt is not on the litany.
The four melts
1. The cold water change. 40% change with tap water five degrees below tank temp. Every crypt in the tank dropped leaves within 72 hours. Everything else — buce, moss, fern — was untouched. The pH changed by 0.2 and the KH not at all, which rules out the two variables the forum blames. Temperature-matching the replacement water has prevented it ever since, across dozens of changes.
2. The root disturbance. Moved a clump twenty centimeters left to "improve the composition." The moved clump melted; the ones I left alone did not. Crypts read their root zone like we read a room. Transplant shock in crypts is real and the forum underplays it because "just don't move them" is not a satisfying theory.
3. The emersed-to-submersed switch. Farm pots melt. This one everyone gets right, but the forum adds a wrong cure: leave them, yes — but also leave the light schedule alone. I once raised photoperiod during a melt to "help," which delayed regrowth by two weeks.
4. The one that followed the rules. Stable tank, no changes, no moves — and melt anyway, starting from the oldest leaves. This turned out to be simple senescence plus my own overfeeding knocking the root tab sideways. The only crypt advice that matters here is boring: a two-year-old root tab is not a root tab.
What regrowth actually looks like
New growth starts from the rhizome, not the stump. Leave every melted leaf stem in place until it lifts out with zero resistance — they still feed the plant and pulling them early tears rhizome buds. Regrowth timing ranged from 9 to 24 days across my four melts, tracking water temperature more than anything else. If the numbers side of your water confuses you, the GH/KH/TDS explainer separates the three dials people keep conflating.
The corrected litany
Crypts melt on osmotic shock and root disturbance more readily than on pH or temperature. Match your water change temperature, stop moving established clumps, and treat "parameters" advice with the suspicion it has earned.
Wendtii remains the best plant in the hobby for people who want drama without effort — it melts theatrically and then quietly comes back better than before.