How accurate is HighGrow?

[Fuse]

Ive got maybe a dumb question, but I just started high grow after reading this thread. I started 3 plants, and gave them all slightly different levels of water, with equal fertilizer. Now, I see that the more water I gave them, the healthier they are (14%, 19%, 25%) after 4 days, but the actual height of the plant is in reverse order, (8mm, 3mm, 2mm). The one that is at 8mm recieved the least water, but it really shot up after I watered them again the 3rd day, evening out the moisture in the soil some by giving plants 1 and 2 a little bit more.

I was just wondering if this is because they are of different strands (Hindu Kush, Himalayan Gold, and Slicks Suprise) , or is it because of the ammount of water as well? I'm assuming I should watch Health more than Height in judging how well I'm doing with these plants?

Oh yah, and how much calcium do you guys add per tenth of ph you want to lower, or something? Like, how much does calcium do. I dont want to use too much and end up with a real low Ph.