2 Pack | 8 Gallons - Acid Blue | Buffered, Low-Fume Muriatic Acid Swimming Pool pH Reducer

Will probably not buy this again but the no odor may win out and I'll get more. It takes twice as much to change the PH as what I get from the pool store and costs more. Still stings when you get some splash on you. Nice not hurting your sinesus or having to hold your breath but cost is prohibitive for me.

Solved my algae problem for a fraction of the cost.