Kalk Precip

[Beverly]

Couldn't wait to test until tomorrow. Here's what I found:

37g:
- SG - 1.026
- pH (10 mins after lights out) - 8.19
- alk - 5 dKH (very low!!)
- Ca - 320 ppm (very low!!)

67g:
- SG -1.024
- pH (10 mins after lights out) - 8.34
- alk - 6 dKH (very low)
- Ca 380 ppm (low)

120g:
- SG - 1.025
- pH (10 mins after lights out) - 8.36
- alk - 8 dKH (a bit low)
- Ca - 380 (low)

Okay. Alk and Ca are low in all tanks, some lower than others. So why would my kalk precip in these alk and Ca starved environments?

Before the precip problem and after the precip, I have used the following to see what difference vinegar made to my tanks:
- 1 teaspoon kalk to 4 L RO/DI
- 1 teaspoon kalk to 4 L RO/DI plus 1 teaspoon vinegar
- kept kalk mixture tightly sealed and let it sit 24-48 hrs

No difference in precipitation using vinegar or not.

Maybe I should buy some new kalk powder and see what it does...