As a glass blower I know that HF etches glass. Thats just hydrogen and flourine. If you spill this acid on your skin and do not get the proper treatment instantly you will die. Nothing in the body stops the flourine atom, nothing.
A guy in Perth about 5 years ago spilt some on his hand at his home chemical lab. He ran screaming into his swimming pool asking for someone to ring an ambulance. The operator thought the phone caller said "Hydrochloric acid" instead of "Hydroflouric acid" and the ambulance did'nt make it a priority one.
He was dead in 15 minutes.
I always ask people..."you could put a lot of healthy things in the water...why Flouride? Who woke up one day and said...'You know what? The world needs MORE Flouride!'"
If it is so good for you why not simply make it into tablet form.
I use a reverse osmosis unit with sediment, carbon and osmotic filter. It removes EVERYTHING.