Crypt Balansae and Spiralis mystery melt

[BluewaterBoof]

I have a 55g that is a couple of months old, loaded with about 14 different types of plants.

The balansae and spiralis were among the first plants added, and did great for the first month. The balansae melted when first added, but new leaves came back right away. The spiralis never melted, and was almost reaching the surface of the water.

About three weeks ago those two plants started going through a continuous melt, and it hasn't stopped. The leaves will grow in and look great for about four days, but then suddenly melt off again. The balansae will melt right off at the bottom of the stem, and the spiralis leaves will look like someone is just rolling them downwards into a big curly fry before melting off.

Tank params are stable:
Amm and trites at zero, trates between 5 and 10ppm
Temp rock solid at 77*F
pH at 7.5
Lighting ~10hr photoperiod with Finnex Stingray
Substrate is pool filter sand loaded with Flourish root tabs
No liquid ferts, no carbon supplement

The head-scratching part is that these plants did just fine for about a full month, and then suddenly started this continuous melting with no changes to the tank that I can determine, and all of the other crypts that are in the tank are nice and healthy.

Any help would be greatly appreciated. I was really looking forward to having a nice curtain of balansae on one side of the tank...I'll be super bummed if I can't get them to stop melting.

[BluewaterBoof]

A shot of the tank:

43997

The balansae are almost impossible to see as they are down to just one leaf per plant, but you can see the spiralis just to the sides of the heater. If you zoom in you can see how one of the remaining leaves is curling downwards into a little ball.

[Silbar]

Your tank looks great. You know WAY more about plants than I do so the only thing I could suggest is to be sure not to plant the crypts too deep (only the roots). Good luck.

[Silbar]

Calcium deficiency – deformed new leaf growth (bent, cupped, curved). Damage and die off of growing points. Yellow margins
:search: Maybe calcium deficiency??

[BluewaterBoof]

Hmmmm... I don't think it's a calcium deficiency. I have Flourish root tabs under the plants and those are loaded with calcium. Also, the leaves look normal and healthy until they get to be about 10" tall, and then just suddenly melt away within a day or so.

[BluewaterBoof]

The fact that none of the other types of crypts are melting is what is confusing me. Crypt spiralis is supposed to be one of the hardiest crypts available, so having that one melt while all the others stay intact has me flabbergasted.

I'm beginning to wonder if the issue is pH-related. My pH from tap is 8.2, but the pH in the tank is lower due to the tannins. Perhaps the brief pH change during the WCs is shocking the plants and causing them to melt? That would explain why the plants do fine for a while and then suddenly melt. But again...why would that be impacting the burly spiralis and not the other crypts? It's the only thing I can think of that may fluctuate within the tank. Hmmm....

The tannins are finally starting to clear out. I'll monitor the pH closely over the next two weeks and during the WCs to see how the balansae and spiralis behave as the pH goes back up.