How to soft wash limestone and what chemicals to use?

I’ve been looking for info on soft washing limestone homes but can’t find any answers. I have a job coming up soon to remove black mold that is very common here in central Texas. Would a house wash mix work on limestone home with black mold using 2 gallons of 12.5% SH to 3 gallons of water down streamed and 5oz of elemonator.

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You see that magnifying glass in the upper right corner? Type in Limestone, have fun and come back for anything further.

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There was just recently a whole thread on it not 2 weeks ago. @John_Martinez

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Yes I saw that thread. I was wondering if anyone has used 2 gallons of 12.5% SH and 3 gallons of water with elemonator with any success. I saw in his thread that the stone can possibly turn orange, is that because the SH mix is to strong? Should I go with a lighter mix of SH to clean limestone? Any help would be helpful.

Ok was reading your post on the other thread. I want to make sure I get the process correct.
So i rinse limestone, then down stream (2 gallons of 12.5% SH mix to 3 gallons of water with 5oz of Elemonator) then rinse again and downstream a mix of F-8 Ox-Brite Oxalic Acid to neutralize and rinse one more time. How much F-8 Should I use per gallon 10oz or 12oz if downstreaming or should I just apply the F-8 to affected areas with a pump sprayer instead of applying to all the stone.

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Downstreaming may not be strong enough, may have to direct apply or use xjet. May take a couple of coats if bad.

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Down streaming SH on the home did nothing to remove the stains.
Call Prosoco and ask for Mike Brennan.
They have a ton of products and some are designed for this stone.
Caveat being I haven’t yet tried their limestone cleaner. However, I will use it next time.
The products they recommend is reklaim . It is about 100 dollars from what I leaned. But once you educate your customer the sale of the product shouldn’t be that hard. Remember our customers hire us because we educate ourselves and invest in the right equipment for the job.
Good luck. Post some before and afters and tell us what you used.


I appreciate the info and please keep us updated, I would really like to know how Reklaim from Prosoco works on limestone.

Just wondering if a high draw 20% chemical injector and straight 12.5% SH work also as opposed to using the x-jet. I’m not a fan of carrying a jug around a property to spray chemicals but if the X-jet is the best and fastest way I will go this route.

This may not work for you, but it did for me. I took this job on short notice and they needed it cleaned by the following morning. I started just before dark. Large concrete and brick patio with 150 ft. of limestone. You can’t see it from the video but, someone had cleaned the limestone before with a turbo nozzle.
I pre wet the limestone before applying a 50/50 mix of 12%. I waited 15 min, then applied again with a hotter mix, using a 12 volt dedicated pump. I rinsed with cold water, 4000 psi, 15 degree nozzle with 200ft of hose


Thanks for the help, I had to apply chemicals directly with a hand pump sprayer which took forever. My downstream injector is 15:1 which made my mix really weak and wouldn’t do anything. I’m going to try and use a 20% draw rate downstream injector from PressureTek and see if this works. According to PressureTek with my 3.5gpm pressure washer the draw rate should be 9:1. Wondering if this would be enough to soft wash stucco and limestone with straight 10% or 12.5% SH.


I use my xjet for jobs that fall between DS and direct with 12v. I have 200’ of hose on my reel for direct with 12v. It takes a few gallons just to fill the hose. For smaller areas or small houses that need more, I use the xjext. I wouldnt want to be without the option now that I know whats up.

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Went by the local prosoco distributor this week and picked up a bunch of samples.


Keep us updated on those products and what each one does and how to properly use each one if you can please. Looking like I’m going to order an x-jet soon, the hand pump sprayer took forever especially using ladder to get to areas up high that I couldn’t reach.

Yeah I climbed on the roof to apply with a pump up sprayer on the limestone home I cleaned. Reminded me of my first few jobs in which I didn’t know better. We’ll figure it out like we always do.

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On my to do list is writing up a training document for the use of each of my chemicals. They are starting to add up. Looks like a chemistry lab in my garage.

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The house looks so much better. I hope the homeowner approves of the results.

Yeah he loved it, he wants me to come back this weekend and do his driveway sidewalk and back patio.

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Know you did it the hard way, but results look good. Nice job.

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Yes I know, I’m getting an x-jet now as it’s better than carrying a hand pump sprayer and the 20% draw rate downstream injector for future jobs. Lesson learned, my 15:1 downstream injector wasn’t enough for this job. I said I do the job without realizing I needed a stronger SH mix that my downstream injector couldn’t do. It’s my company’s reputation and I’m barely starting, I didn’t want to tell owner I couldn’t do job after I said I could since I hadn’t educated myself at the time and realized limestone needed a stronger mix I couldn’t do with my equipment like I thought I could. I knew I would still be able to do job with a hand pump sprayer and would have to work a lot harder since I didn’t have the correct equipment but I made sure it came out good because it’s my companys reputation on the line. Luckily it only took me 2hrs to do the front house which is all he wanted done. Thanks on the advice of a stronger SH mix i really appreciate the information.