I had to go to the pool store to get a tail scrubber for the polaris. While I was waiting I overheard another customer ask the clerk about something to rise the alkalinity in their pool. The clerk asked how big the pool was then picked up two 5 lb buckets of something called Alkalinity-up. The price was $14.95 per bucket. The customer paid and left.
When I got up the register I asked the clerk why he recommended the Alkalinity-up instead of a 50 lb bag of sodium bicarbonate they had for $22. The clerk told me they were two different chemicals. Alkalinity-up was sodium hydrogen carbonate not sodium bicarbonate and was much more effective. I almost choked trying to keep my mouth shut and another guy standing next to me looked at me and rolled his eyes.