My question is: Who does the pool maintc at your house? If its you, then he doesn't need to know what you use. If its him, do what John above recommends by showing him labels or buy the chlorine at the pool store.

If it was my DH, I would simply tell him to put a sock in it and get over it. I do the pool maintc, I bought the pool, all he needs to do is swim and enjoy - but thats just me and thats just him (he never even blinked when I told him I had just dumped 120# of solar salt into our pool)