Hey All,
I have this weird stain on a sign Im working on. I thought it was calcium, but f9 efforecence remover didn’t touch it up to 1/4(though it did fizz up) any thoughts? There appears to be some kind of caulk upon closer inspection, any idea of what it could be?
Your chems might just be having a hard time fighting through that sealer; looks to me like somebody tried to seal on top of the efflorescence to see if that would fix it
I sure hope not. 
If it won’t come off its not a big deal. The property manager isn’t dead set on it as its part of a larger project, but I said I would give it a try.
I had a similar issue last week, tried muriatic acid 10-1 then 4-1 with no good result. Tried a turbo nozzle but the entire grout line started coming out. My guess is calcium build up but concrete is still on my learning curve.
Wait, when I looked at this on the computer earlier it looked like the glossiness was coming from a sealer. Now, on my phone, I realize it might be super wet from you having just washed it. If that’s the case then disregard what I said earlier
