11/10/2026
HOW MUCH CHLORINE (SH) SHOULD YOU REALLY BE USING TO WASH A HOUSE?
We're getting a lot of enquiries about SH concentrations for house washing. I honestly thought this would be common knowledge by now!
I'm guessing many questions are coming from newcomers, so here's some advice based on what we've learned over the years, including a few expensive lessons from 2020.
SOME HISTORY FOR CONTEXT.
Back then, many equipment suppliers and industry "experts" recommended around 1.25% SH for house washing. We never did, never have and never will recommend that as a standard house wash solution!
Our starting point has been 0.5% SH since 2020, less than half that concentration. We understood enough chemistry back then to question why so much chlorine was necessary. Today, after years of research, testing and practical experience, our understanding is considerably more advanced.
We developed our methods out of necessity and a genuine desire to improve cleaning results, protect surfaces, reduce chemical use and look after our own wellbeing.
Not because we were selling equipment or associated with the right people. Believe me, nobody wanted to be associated with us back then! The industry "brotherhood" made that pretty clear.
Interestingly, six years later, some of the very approaches we were ridiculed for are now being promoted by those who once dismissed us. Some even talk as though they'd known it all along!
SO WHAT DID WE DISCOVER?
In 2020, we discovered our proportioning manifolds weren't necessarily delivering the SH concentrations we believed they were. The GF metering valves aren't defective. They're quality industrial flow-control valves doing what they're designed to do.
But they're not chlorine concentration meters, nor were they specifically designed to determine the final SH percentage in a softwash system. Pressure, temperature, viscosity and flow rates can all influence the final output. Just because your manifold is set to a particular percentage doesn't mean that's what's coming out of your hose.
Back then, much of our chlorine was 10% strength. Today, 12.5% is common, meaning 25% more SH at the same draw ratio. Washing a roof at what you believe is 2%? You could actually be applying 2.5%, exceeding a manufacturer's 2% maximum.
We genuinely felt misled and tried to warn others. Unfortunately, we were ridiculed, blocked from forums and shut out of the conversation. Something similar happened when we released our own softwash soaps and questioned accepted industry practices.
SO WHAT DID WE DO?
We removed the manifold and converted our existing chlorine tank to batch mixing. Our chlorine consumption dropped dramatically, saving us thousands of dollars a month while maintaining excellent cleaning results.
Our wellbeing improved too. No more burning eyes and irritated skin from unnecessarily strong solutions. Less chlorine, lower costs and greater control.
OUR ADVICE?
For better control, consider removing your manifold and converting your current chlorine tank into a batch tank, provided the tank and plumbing are suitable.
Don't want to remove your expensive manifold?
You can consider diluting your chlorine supply. A 50:50 mix of 12.5% SH and water gives approximately 6.25% SH, potentially making lower concentrations easier to proportion. Setting your dial to 0.75% SH should be close, but you still need to verify your actual output. Dilution doesn't automatically make a manifold accurate, and diluted chlorine can have a shorter storage life depending on conditions.
You're almost batch mixing anyway!
SO HOW MUCH SH?
For normal house washing, we recommend starting at 0.5% SH in the finished solution. It's not a hard and fast rule. Surface condition, organic growth, dirt and environmental conditions all influence the decision.
HERE'S A SIMPLE DADS 100 L BATCH MIXING EXAMPLE.
For a normal house wash targeting approximately 0.5% SH, using chlorine at 12.5% strength:
4 L of 12.5% SH
200–300 ml DADS House Wash Surfactant
200–300 ml DADS Surface Helper (optional, when dirt and grime are present)
Top up with water to a total finished volume of 100 L.
That's it!
Attached ready reckoner for download. Right click and save as.
Always check the actual strength of your chlorine, as it deteriorates over time, and only mix compatible products using appropriate safety procedures. You don't need a complicated chemistry set or unnecessarily strong solutions to get good cleaning results.
For roofs, follow the manufacturer's cleaning guidelines.
WHERE DO DADS AND ULTRASOFT FIT IN?
DADS cleaning products are based on our original formulations, further developed and improved between 2021 and 2025. Professional performance, excellent value and responsible chemistry remain our priorities.
Ultrasoft takes that knowledge further with purpose-developed equipment, products, specialised cleaning processes and professional training.
Our exact Ultrasoft methods, products, ratios and techniques remain exclusive to licensed operators.
There's a big difference between owning or selling cleaning equipment and truly understanding how to use it.
Ultrasoft wasn't developed to follow the industry. It was developed because we believed there was a better way. Now the industry follows us!
And six years later, we're still researching, learning and improving.
DADS — A Helping Hand.
Ultrasoft — Responsible Chemistry.
