Since he was a baby(he's 14 now), any time he's been in a chlorine pool whether private or public, his eyes burn horribly bad. Badly managed private and public pools cause burning eyes, and people mistake the smell of chlorine as a sign that the owners are keeping things clean. The fact is that if you smell strong chlorine at a pool it isn't a good sign- it means that the pool's chlorine is overwhelmed with contaminates and you're smelling the combined chloramines. As others have said, overly high or low pH is the cause of eye discomfort.
Just wondering if there are any household products to substitute for Baquacil. Plenty of substitutions for commonly sold "pool chemicals"...such as baking soda as you've discovered, regular borax and chlorine bleach from the laundry aisle.
We've used it for 15 years with great success, but it's getting very pricey. I just about fell off my chair reading you say you were going to order $500 worth of chemicals! OMG.. I probably spend between $50-100/year for my pool care. Maybe. I have a salt system chlorine generator that chugs along happily and makes our pool easy to care for. I've never once had algae or cloudy water.
We have an above ground 27'x52" pool with a sand filter. Our water is usually clear, sometimes if I neglect to add shock on time it clouds, but is corrected quickly. I have substituted baking soda for the alkalinity increaser. Just wondering if there's anything else out there.