Now, we have backwashed several times as we had a filter problem (replaced the old panel) and had plenty of splashing with a bunch of kids over the summer. So, we lost volume. Volume replaced out of garden hose.So I'm going to be the nit picker todayWhat is a balance pack? Sounds like some kind of diet supplement!!
Evaporation doesn't decrease the levels of CYA, it actually increases it ppm wise. Evap is just water going away. That causes the stuff in the pool to be MORE concentrated. When you replace the water, it goes back to what is was before the evaporation. Splashout, draining, backwashing and bathing suits will help to lower CYA and other chems too.
Balance pak is what bioguard calls NaHCO3- or baking soda.
I wasn't going to get my water tested without buying something from them.