PM sent on the bulbs.
I like them. I originally purchased them for my 24 Azoo tank and purchased more once I started planning my new tank. I actually have 4 of them: 12K, 20K, all blue and all red. I have tried more more bulbs for my set-up, but to me, what I am looking to achieve, it was just to bright for a Azoo aquarium.
For calcium and Alk, I dont add anything. I do 50% water changes twice a week, occasionally only once if I am too busy at work and have had no issues with calcium or alk demand.
Mike