An age old question: SH downstream mix to suction ratio

Hello everyone.

This is my first post here. I’ve been lurking for awhile and finally joined. I haven’t started up a business yet but I will be soon. I want to get some practice in first so I dont mess up too bad at a customer’s house. I’ve searched for this and read what I found but I’m hoping for an exact understanding with the equipment I’m using. I may get something else but for now lets just focus on what I have and how to use it.

The machine is a Pressure Pro EB4040HC. 4000 PSI @ 4 GPM. I bought a DS injector that siphons but I’m not getting the cleaning action I see on videos I’ve watched.

The DS is this one:

The Q&A at the website I bought it from says:

This soap nozzle will provide a dilution ratio of 20% solution to 80% water. So the ratio would be 4:1, water to detergent

I mixed a small batch to test wash my greenhouse. It had a lot of mildew on it. It is cinder block with an aluminum frame on top.

I used 1/2 gallon of 12.5% SH, 2 gallons of water and 3 oz of Elemenator. This was a mix recipe I found on YouTube.

Am I doing the math here correctly for the final strength?

12.5% SH diluted with 4 parts water makes a 2.5% SH solution. That cleaning solution is being further diluted with 4 parts water leaving me with a .5% SH effectively. Yes or no?

What is the final strength I am trying to get to? 1.25% is a number I’ve seen thrown around. Do I have to use a different strength on stucco?

The greenhouse cleaned up nicely but not with a soft rinse. I had to use a turbo nozzle at 2500 PSI. What pressure should I run the machine at to spray the soap and rinse? I was using 1500 PSI and I could see the white soap foam but it wasnt too thick. I think I added too much water to my mix.

Thanks for your help.

Basically what you bot is a cheap version of an xjet. That’s not a ds injector. With your machine it will normally pull about 9-1 with regular ds injector. Depending on how bad mildew is you normally want about .7 - 1% net. Stucco you may need stronger, depending on how dirty. You should see the mix start to work within about 5-7 min. If not, use stronger mix. Get you a regular DS injector (about $14), about 4’ of 1/4 hose and a filter and you’ll be good to go for softwashing. You’ll need a jrod or m5ds nozzle. You’ll be able to clean anything you want pretty much with what you’ve already bought and this.


Thanks for the info Racer!

Being such a noob I still have questions about your answers. :grin:

They told me it was a DS injector. So, if it’s not, can you please explain the difference between what I got and a real DS Injector is?

Since you gave me the % and not a different way of calculating it, does that mean I did the math correctly in my example?

How much stronger for stucco? What is considered too strong for stucco or to use in general. I’ve seen a few mentions of guys using “too hot of a mix” and causing problems. I dont want to be one of those guys.

Does the “regular DS injector” go inline before the hose? I chose this one so I wouldnt run chemicals through the hose.

This is the type he is talking about
IMO 3-4% is good for stucco. Too strong wont really hurt the stucco but its a waste and more of a danger to surrounding plant life. 4% is where I start to get very concerned for plants and watering


Where does it go? Right after the pump? Does running bleach through the hoses and gun ruin them over time?

Can I put it at the end of a 100’ hose and then run a 25’ or 50’ hose? I want to be closer to the chemical so I dont have to go back to the machine if I want to switch it off.

it goes between the pump and the hose reel. You’re generally only running about 1% or a little less through the hose. It wont hurt the hose. They dont last forever anyway.
I supposed you could put it just before the gun of you really wanted to BUT you would need to run a hose to your mix tank or carry a bucket. Might as well do the xjet if you really dont want to leave the chems in a tank or bucket at the street and wat the control at the end of your hose.