Help for a new guy?

I’ve been doing research and trying to gather as much information as I can but I still don’t seem to understand DSing.
Am I supposed to pull straight chem?
Or am I pulling a diluted mic to even further dilute with the DS?

Figure out the ratio that your injector pulls. It is typically 1:10 or 1:20. With 1:10, pulling undiluted 12.5% will get you a roughly 1% solution coming out on the surface.

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It’s not so much what your injector is rated and more how your machine is set up.

For example, the GP 1.8 injector on a 4/4 machine with 50’ of hose will suck down SH in no time. Put the same one on the 5.5/3500 and 200’ of hose, and you might get .8% on the house.

I run 2.1’s on my (now) 8/3000 and it’s probably around .5%, pretty weak.

Basically if you’re using a smaller machine you’ll want to dilute it at least 50/50.


Thank you all for your feedback

This is probably the one area where I’m still having a hard time wrapping my head around. Is there a calculator somewhere to use or can someone help me understand the calculations that go into it so I can make my own?

My DS is a 1:7, so if I run 50/50 on 12.5 through 200’ of hose, what % am I looking at?

You’re overthinking this. Forget percentages.

If algae turns brown in a couple minutes you’re golden. Adjust accordingly.

And that’s not something I came up with, the veterans on here told me that when I first started.


If that helps you picture it a little better.

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I believe with 8 parts, you are looking at 1.56% - that is, you are drawing straight SH. If you’re drawing 6.25, or 50-50, then it’s 0.78%.

Would 4/4000 be considered a smaller pump?

Yes, a 4/4 is considered the smallest viable cold water machine for professional use. Some of the hot water guys use 3.5’s but that’s on a different level.:smirk:

Thanks for asking this. I got on here just now for something similar. Im gonna run a 4400/4. And was looking for ratios. Also dumb question I’m pretty sure but can I just use a 5 gallon bucket to suck the mix out of.

Yes you can use a 5 gallon bucket.

Yep, however you need to either:
A. Have a separate bucket of water that you can throw your drop stick in when rinsing or
B. Buy an injector bypass kit (search for it on

The bypass kit will allow water to be routed around the chem injector so you can rinse without drawing chem. Simply turn the ball valve on way for water and the other way for chem. I’ve had one for a year now and can’t imagine not having it.

From what I’ve learned from others and from my own experience, experiment with your ratio until you have something strong enough to get the green off in 5-7 mins. Start with a 50/50 of bleach and water…spray a section of the house. Change the dilution accordingly. Worrying about what percentage is coming out of the gun isn’t that important. Also, if you add or subtract how much hose you have, that can affect the strength of your mix. For example, if I’m pre-treating a driveway, I will sometimes put on a 50’ section of hose and a 2-3gpm injector so the mix is really hot. For a house wash, I’m fine with 200’ hose and a 3-5gpm injector. Typically, longer hose will draw less chem.