Has anyone here ever used Spartan M*95 for hard water? I saw at my local supply house. Runs about $12-$15 per gallon from the wholesaler here.
I thought it might be worth it to try it out, anyway, perhaps on an old window that nobody cares about.
Link here: M*95® | Spartan Chemical
SDS indicates it is Hydrochloric Acid.
We used to use Spartan for our supplier about 10 years ago for our commercial janitorial. I can tell you M95 worked wonders on toilets that had calcium build ups and rust. So as for its effectiveness it works fantastic. I have no input on how well it works on windows. I do remember accidentally dripping a drop on concrete and it instantly turned it white so it is very strong. It would probably need greatly diluted before being used on a window because anything else it touches is toast.
