How are you applying it? Downstream, xjet, 12v, pump up? What % is hitting the wall?
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I was also using a tip that pulls straight out of a bucket. So it is diluting with water but right out of the tip. Should I apply straight bleach with no water?
Yes. You won’t touch that downstreaming box store bleach. Use a xjet, 12v or pump sprayer.
If he’s downstreaming only 1/2-3/4 of a per cent is hitting the surface
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Looks like he’s using a bootleg xjet. I’m not familiar with that.
Whatever, however you do it. Get 3-5% hitting that wall. If that doesn’t work move onto other chemicals.
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Nailed it. He needs to try 50% bleach via a pump up sprayer in an inconspicuous spot. If that doesn’t work 100% via sprayer. Keep testing until you find what works.
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Get you some 12.5% SH from the pool supply. Put straight SH into a pump up with some surfactant and maybe a little bit of Sodium Hydroxide (if you are limited to lowe’s or home depot, go to cleaners and look at chemical listing - find a degreaser that list Sodium Hydroxide as one of the first chemicals) and spray on wall. Spray every 5 minutes for 20 minutes. Rinse. I wouldn’t use high pressure as it looks to be some kind of coating over brick that I would be afraid of chipping off.
Pump Up Sprayer
1/2 gal SH
1 oz surfactant
2 cups Sodium Hydroxide
Try agitation with a bristle brush during the dwell - see if that helps.
If this works, then try 1:1 SH to water. Then go to 1:2 SH to water. Keep diluting and testing in a small spot until you find the right strength to get the job done without using more chem than necessary.
Around here, 99% of the time it take me 2,3,4 or even 5 applications to keep mold off masonry as it get rooted deep in the pores. Nothing like vinyl or painted surfaces. After each application rinse well and you should see it lighten in color with some areas or spots coming clean.
If that does not work, then try:
Try a 10:1 muriatic acid solution - test in a very small spot. Increase to 9:1, 8:1, 7:1 up to 5:1. Again, use a spray bottle and test in a very small spot say in a lower corner that won’t be visible. Try aggitation during dwell (3-4 minutes). Only mix acid with water, do not add other chemicals.
If that does not work, then you will need to look at professional chems such as One Restore, EBC, or Reklaim from Prosoco are a couple of options.
Good Luck.
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You could x-jet a strong sh mix but downstreaming isn’t going to do much on those dark streaks.
Looks like it’s a very ugly parge coat over maybe a deteriorating brick? Doesnt look like shotcrete. Either way up your sh strength. Xjet or direct application. I don’t think 6% ds out of the bucket is going to cut it.
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It’s just black mould. I clean stuff like that every day!
12.5% SH, surfactant with a 20% chemical injector will work downstreaming.
If not, you need to x-jet or apply 50/50 with a sprayer.
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I can’t find 12.5% only 10% chlorine, but that’s looking local.
What exactly is surfactant?
10% is going to work way better than strong bleach. Get that.
Surfactant is to make the water wetter/reduce the surface tension.Basically all soaps contain them.
You need a chlorine stable one though - or it can create toxic gas/heat/erupt/emulsify when mixed with an incompatible soap.
Have you called any pool supply stores? If they don’t carry it they can probably tell you where to find it.
Just do this -
Got to Home Depot and get a gal of Chlorinating Liquid( it will be 10%)
Get some Dawn (yeah I know./…)
Pour bleach into pump up sprayer. Put 2 tablespoons Dawn in. Pump up and spray on wall. Let dwell 5-10 min and then rinse.
Is it clean now? If not at least lighter? If lighter, do again. Rinse and repeat until clean.
Report back what happens.
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Already got it. The problem with a pump sprayer is the wall is so high the pump up will not spray as high as that wall is or even close to it.
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You’re only option is to buy an x-jet.
I wouldn’t do the whole wall with a pump-up, just an area to get my solution down to what works.
Once I got that, then I would go x-jet or 12 v or DS depending on how strong a mix I would need to get it clean.
