Do I need to add calcium?

After a partial drain last week i brought my cya and hardness down some. Then we had heavy rains a few days later. Now my hardness registers 0 on my HTH 5 way test kit. Cya is still high (but that is another post).

My pool is a 29' round AG vinyl liner. I know a high level of hardness doesn't matter in a vinyl pool but what about no hardness at all?

I remember reading in the forums there was a problem with the HTH hardness test. Went looking for the thread couldn’t find it.
As for hardness with a vinyl liner I will refer you to this thread.
Steve

The documented problem was with the AquaChem kit but I believe the HTH kit has a similar problem. Here is the thread
http://www.poolforum.com/pf2/showthr...light=aquachem

Thanks Evan
Looked for that post for nearly 30 minutes.
Steve