Concrete Cleaning

[cooked]

Algae prefer an acidic environment, so using hydrochloric acid etc will only solve the problem temporarily. 

Power cleaner.

Splash bleach about and leave it for ten minutes.

Quick going over with the power cleaner again.

I can also recommend charred rice husks, though of course they tend to get swept away.

[Yellowtail]

That duck toilet cleaner will clean and kill it quickly and easily

[kiteman9]

I have used    https://www.lazada.co.th/products/5l-ph-hydrochloric-acid-5l-ph-down-minus-chemical-balance-in-pool-water-i2005346633-s6464528670.html?exlaz=d_1:mm_150050845_51350205_2010350205::12:12654756915!117524295342!!!pla-294682000766!c!294682000766!6464528670!315642399&gclid=Cj0KCQjwlMaGBhD3ARIsAPvWd6hvKWvMKtyFwb_BuRaphxBX0Rixg7wWSNfbbiT4C5LXGBO7cUzzX6caArijEALw_wcB.    

Common Uses for Muriatic Acid

Clean and etch concrete—Muriatic acid is extremely effective at cleaning concrete walls and floors, including both poured concrete and concrete block. It’s particularly well suited for removing stubborn efflorescence, which is a white, powdery substance that forms on masonry surfaces. (Efflorescence is caused by salts leaching out of concrete.) And when applied to concrete, muriatic acid also etches the surface, which prepares it for a fresh coat of paint or stain. To clean and etch concrete, mix one part muriatic acid to 10 parts water. Brush or spray the acid solution on the concrete, wait eight to 10 minutes, then neutralize the acid by spraying the surface with a mixture of one cup of ammonia in one gallon of water. 

 

[Yellowtail]

23 minutes ago, kiteman9 said:

I have used    https://www.lazada.co.th/products/5l-ph-hydrochloric-acid-5l-ph-down-minus-chemical-balance-in-pool-water-i2005346633-s6464528670.html?exlaz=d_1:mm_150050845_51350205_2010350205::12:12654756915!117524295342!!!pla-294682000766!c!294682000766!6464528670!315642399&gclid=Cj0KCQjwlMaGBhD3ARIsAPvWd6hvKWvMKtyFwb_BuRaphxBX0Rixg7wWSNfbbiT4C5LXGBO7cUzzX6caArijEALw_wcB.    

Common Uses for Muriatic Acid

Clean and etch concrete—Muriatic acid is extremely effective at cleaning concrete walls and floors, including both poured concrete and concrete block. It’s particularly well suited for removing stubborn efflorescence, which is a white, powdery substance that forms on masonry surfaces. (Efflorescence is caused by salts leaching out of concrete.) And when applied to concrete, muriatic acid also etches the surface, which prepares it for a fresh coat of paint or stain. To clean and etch concrete, mix one part muriatic acid to 10 parts water. Brush or spray the acid solution on the concrete, wait eight to 10 minutes, then neutralize the acid by spraying the surface with a mixture of one cup of ammonia in one gallon of water. 

 

 

Why can you not just pour it on?

[tifino]

8 minutes ago, Yellowtail said:

 

Why can you not just pour it on?

pouring it on will inundate the concrete, and take longer to rinse off...

 - the longer it is on the surface - the more 'eating away' of the 'concrete before it's rinsed off

[cooked]

17 hours ago, kiteman9 said:

I have used    https://www.lazada.co.th/products/5l-ph-hydrochloric-acid-5l-ph-down-minus-chemical-balance-in-pool-water-i2005346633-s6464528670.html?exlaz=d_1:mm_150050845_51350205_2010350205::12:12654756915!117524295342!!!pla-294682000766!c!294682000766!6464528670!315642399&gclid=Cj0KCQjwlMaGBhD3ARIsAPvWd6hvKWvMKtyFwb_BuRaphxBX0Rixg7wWSNfbbiT4C5LXGBO7cUzzX6caArijEALw_wcB.    

Common Uses for Muriatic Acid

Clean and etch concrete—Muriatic acid is extremely effective at cleaning concrete walls and floors, including both poured concrete and concrete block. It’s particularly well suited for removing stubborn efflorescence, which is a white, powdery substance that forms on masonry surfaces. (Efflorescence is caused by salts leaching out of concrete.) And when applied to concrete, muriatic acid also etches the surface, which prepares it for a fresh coat of paint or stain. To clean and etch concrete, mix one part muriatic acid to 10 parts water. Brush or spray the acid solution on the concrete, wait eight to 10 minutes, then neutralize the acid by spraying the surface with a mixture of one cup of ammonia in one gallon of water. 

 

Well there you go. Acid is good for removing alcalic compounds such as salpeter efflorescences, but no good for removing algae. The algae will disappear but as they like an acidic environement will return even stronger than before.