His expertise is in building pools and I've developed a level of expertise in maintaining mine. That's my responsibility as a pool owner .....
I think building a pool and maintaining one are closely related. PB's sell us equipment that is maintenance and water chemistry related - chlorinators, in floor cleaning systems, swg, UV systems, and so on. So, expecting them to know about the pros and cons of each item is not really asking for too much. I can certainly understand why trades / subs like the gunite guy or the landscape guy or even the tile guy does not know much about water chemistry. In some ways, I would also excuse the pool designer from having detailed knowledge about everything pool related - but it is a stretch for me to comprehend that a PB does not have basic water chemistry knowledge.