I was at the pool store returning some over-priced parts and had them test the water. Calcium hardness was 130 and they recommended adding 28 pounds of Hardness Plus.
Based on what I've read here, it was my impression that I didn't need to worry about the calcium hardness level since I have a vinyl pool. When I told this to the tester, he said he had never heard any such advice. According to him, if the calcium level is low, the water will basically suck calcium out of the liner and cause it to degrade faster.
When I googled the issue, I saw somebody post the following on another site in response to a similar question:
Any thoughts on this? A guess is we probably have 2-3 years left on the liner. Maybe more. But I'd sure hate to do anything to rush it."Ignore Calcium Hardness In Vinyl Pools"
I have been in the pool business most of my life... 40+ years... Part of balancing the water daily thru weekly includes Calcium Hardness... If the level is too low it will try sucking it out of the liner! I assume you have never seen a shribbled liner or decayed equipment from not caring about the Calcium Hardness...
True on the part with concrete, gunite, tile surfaces... Pool builders neglect to tell gunite pool owners to brush the walls a solid 14 days so it doesn't get prickly, etc... Plus to test the water daily, too...
Note: Always have the pool's water tested professionally for everything when 1st opened and adjust what's off... Then test it again professionally a week later to be sure it is balanced...
Note: The type of chlorination and added water will dictate if the Calcium Hardness is being effected, too...
Note: Pool equipment and pool surfaces are eaten away and break down from neglect and poor water balancing!
I tested chlorine and PH this morning, but here are the rest of the pool store test results. PH was about the same as me. I would have put it at 7.5, but I tested about 8 hours earlier. My chlorine level with the Taylor kit was also higher, but it was sunny, in the 90s and kids spent about 5 hours swimming today so it probably dropped.
Store test #s:
Free chlorine: 2.0
PH: 7.6 (I'm going to try and drop it a bit tomorrow)
CH: 130 (they recommended 200-400)