"Pool opening service" was what you paid for, and not necessarily what you received. However your service may have been equipment only, and may not have included any chemicals. Many, many guys who work on pools know NOTHING about pool chemistry, and avoid it like the plague.

Pool store testing is highly erratic in quality, but mostly bad. The only way to find out what's REALLY in your pool water, is to test it yourself. Once you do, you may well discover that your local store is one of the few that do provide accurate testing. But until then, you won't know.

However, the store is correct on at least one point: IF you have zero CYA, THEN you will not be able to maintain a consistent chlorine level. Without stabilizer, you can lose ALL the chlorine in your pool -- regardless of level -- in 4 hours of full sun.

. . . membership updated.