I do not know what level purity of salts you need to start with to make your own cell salts, but I looked at one of the suppliers I use (as a science teacher). Fisher Scientific has calcium fluoride available in 100g and 250g bottles.

https://www.fishersci.com/shop/products/calcium-fluoride-precipitated-97-thermo-scientific/AAA1017630#?keyword=calcium%20fluoride
https://www.fishersci.com/shop/products/calcium-fluoride-99-pure-anhydrous-thermo-scientific/AC218251000#?keyword=calcium%20fluoride

If 'lab grade' salts like these would be appropriate, I can pull together a list of companies I've purchased from for lab supplies.