Calcium deficiency, or ...???

[Milan]

I need help with my plants. In the last few days leaves on some plants (ie. Hygr. Polysperma, Bacopa Car.) became shrunken, cupped or curled if you wish (see the pictures below), so I suspected the Calcium deficiency, according to what I read about it on the net. Today I went to a LFS and bought a Calcium test, and measured 60 mg/l Ca++. Now I'm completely confused ... This should be enough!

Another observation:

Lately, since ~ 2 months ago, there are snails in the tank (taking Ca for their shells, perhaps?). I think they are ramshorns, but they don't get bigger than 1/8" (lack of Ca again?)

Here are the complete (available) water parameters:

NO3 = 5 ppm

PO4 = 0.5 ppm

GH = 10.8 dGH

KH = 5.6 dGH

pH = 7.1

CA++ = 60 ppm

Other Info:

Tank - 29 g

Light - 65W 6700K

DIY CO2

So far I've been fertilizing with K2SO4 only + TE, since NO3 and PO4 have been always on targets. Actually I increased the dosing of K since couple weeks ago when I had potassium deficiency. Current dosing is @ 2 ppm/day. Now, I'm wondering if too much K can do this? According to any reference I have come across, there is no harm in K overdosing. And by the look of it, ... Is the test I bought fooling me, or I'm badly missing something?

Please help!

[andyg]

Milan, as I mentionned in an earlier post, your NO3 is a bit on the low side. You should aim for a 10-15ppm. Now I'm not saying that you have an NO3 deficiency but, it may be a limiting factor to the uptake of some of the other nutrients.

If you decide to up th no3 have a look at the following article.

http://www.csd.net/%7Ecgadd/aqua/art_plant_nitrate.htm

[Milan]

Thanks Andy,

I think I found something interesting. Too much K may interfere with Ca uptake and possibly some other macros. That's why it looks like Ca deficiency, while there is plenty of it. So, my best bet would be that it is potassium OD, contrary to the theory that there is no harm in too much K.

I did a 50% WC, and I'm cutting down the K dosing. Also, I think you are right about NO3 levels. I'll shoot for 10.

Second thing, my CO2 according to the values above, is @ about 13 ppm, which I should bring up. I'll add another DIY bottle or try to lower the pH by adding vinegar.