Two Part Solution Problem- Help!

[straightrazorguy]

I am trying to tap into the collective wisdom here. I started my two part solution system a few months ago, as my kalkwasser additions no longer kept up with my growing coral collection. I automated the two part a month ago (before that I was doing it manually, as I was having issues with my Reefkeeper Elite head unit). I currently use Dowflake Calcium chloride and baking soda solution, dosed using BRS peristaltic pumps.

After some tweaking I found that dosing both CaCl and Alk solution for 36 minutes per day (split into four doses per day) gave me stable readings of 400-420 for Calcium and 7.5-8.5 dKH for Alk. Unfortunately a couple of my colonies started STN-ing. I checked the parameters again and I found the Alk started climbing over 9 dKH for no apparent reason. Yesterday I stopped adding Alk solution altogether, in the hope to let it fall naturally. I left the Kalkwasser dosing unchanged, i.e it keeps up with evaporation. This morning the Ca was at 440 and the Alk was 9.6dKH!

I can't make sense of this: I repeated the readings, tested for Mg which I found to be 1480. It doesn't make sense! I need some HELP!

Tank stats:

- 3 ft cube (150 gal) mixed display tank.
- Sump: approx 30 gal
- Skimmer: RLSS 6i
- Refugium: 55 gallon inline refugium full of cheato and live rock. Crawling with pods
- Corals: combo of SPS and LPS. Mostly small to medium frags.
- 10 Fish: 1 Yellow Tang, 1 Harlequin Tusk, 1 Copperband Butterfly, 1 Anthia, 1 Tamarin Wrasse, 1 Cleaner Wrasse, 2 Percula Clowns, 2 cleaner shrimp
- Params: undetectable nitrates and phoshates
- Reactors: ROWAphos, Biopellets, Kalk stirrer dosed via BRS dosing pump to keep up with evaporation

The tank was set up in April, when I upgraded and transferred all the live rock and corals from the 55 gallon that is now the refugium.

I started a tank journal which I sadly neglected:

http://www.canreef.com/vbulletin/sho...=107802&page=2