Hard Water Stains


@squidskc thought you my be able to help me. I washed an indoor pool deck that had a ton of hard water stains and nothing we tried on the stains seemed to work. Would you by chance have an idea on what could get hard water stains out of concrete? I also have a potential customer that has hard water stains (not rust) on his new vinyl siding what would work on those?

Muratic acid works well on hard water calcium stains. Just depends on what the surface is. Muratic can destroy brick / pavers /and concrete

1 Like

Oxalic Acid and F9 Barc

Oxalic does next to nothing on calcium deposits

1 Like

zep’s calcium deposit product works well enough.

1 Like

What type of surface is that sign?

Some type of metal.

got a pic. We never get those here, extremely soft water.

Left is before…right is after (You can’t really even tell a difference)

What have you tried?

House wash mix (Did a great job of cleaning the concrete of grime), big box hard water stain remover, vinegar, wire brush. Nothing was even touching it.

So you haven’t tried Oxalic, or F9?

I have not and I would try it, but we do not have access to the pool deck any longer. They were just doing a drain, clean and refill. I will try the oxalic on the hard water stains on the vinyl siding though.

I know this is an old post but what else did you do this sign besides apply and PW off? Thanks

Nothing. I didn’t water it down though and it took like three applications.

1 Like

And it was more of a rinse then pressure.