Did I get the wrong surface cleaner?

Hey guys,

Sorry if this has been posted before but I’ve tried digging deep into the forums but still couldn’t find the answer I was after.

I’ve recently purchased a 3500PSI 4GPM pressure washer and along with it a 21" Surface cleaner (3 x rotary arms @ 25020). I’m having major issues with stripes and areas are still not cleaned evenly as I want them to. (I’ll attach an image) I’ve tried using a 1:2 SH mix pre/post and adjusted the speed to a slower pace yet the issue remains.

I’ve looked at a nozzle chart as someone has suggested at the following URL:


But I have no clue which chart I should be focusing on.

The only options I can assume is correct is to order in 3 x 15020 nozzles or to use a 1:1 hotter mix. If these solutions don’t do the job do you guys agree that I’ve purchased the incorrect SC for my unit?

Sorry for any ignorance guys and hopefully you guys can assist me in this :slight_smile:


With a 4 gpm machine you probably should’ve stuck with a 16" surface cleaner. A 21" will work but you have to move very slow. Although, with 3 arms you’re only getting about 1400 psi out of it and no way to get anymore with a 4 gpm machine. You really need a 2 nozzle instead of the 3 arm/nozzles. Pre and post treating will help but you’re still weak on the psi and you’re already using the smallest nozzles. Ordering 15020 like you mentioned only changes the degree of the pattern. Surfaces cleaners should use 25 degree that you currently have. The last two numbers are the orifice size. So, 25020 is a 25 degree tip with a 2.0 orifice.

Look into getting a 2 nozzle Whisper Wash Ultra.


Hey @marinegrunt thanks so much for the swift reply.

I had a feeling the 21" was too large for my unit (wish I did more research). I’ll check tomorrow if i can replace the product with something smaller if not, do you think a 2 nozzle single arm like you suggested @ ~1750PSI is viable for driveway cleaning ? I’ll stick to your advice and keep the nozzles at 25020 and not go to a 15020.

Thanks champ

Just so happens I may be selling my 16” Ultra. Too bad he probably isn’t local.

I would’ve love to snatch it off you @dcbrock however, I’m not a local at all.

Hoping my vendor will allow me to make a switch as I’ve only used it one time.

They might. Clean it up really good.

Once you go to a 2 nozzle you probably want 2503 nozzles

Wouldn’t that only give him 1750 psi @ 4gpm?

@dangthatsclean, you could try swapping to 25015 on your 3 bar sc before moving on from it. I agree that a 16” 2 nozzle setup would be better, though. The 25015’s would push you up to 3250, which is a little sketch for residential concrete.

Hey @infinity thanks so much for the advice. You’re right I could go for a 3 x 25015 to get about 3200-3250 PSI but from your experience how likely is that to etch concrete? Could this also be an option? Keep my 20” and change it to a two nozzle setup running 25025? I know this setup is optimal for a 16” at 2500 PSI 4GPM but what difference will it be on a 20”.

Sorry if these questions are annoying to answer thanks champ!

In my experience? No idea. I have used a (really cheap) surface cleaner about 3 times in my pw’ing career. I’m just good with the math and theory of it.

If there’s a chance you can exchange this for a 2 nozzle 16”, that’d be my first choice.

You’ll get a chuckle out if this, but I’ve been using 2502’s on my 4 nozzle 19” and my 5.5/3500. It’s really slow work but my striping is down a lot from my 2 nozzle. Best I can estimate at 50’ of hose it’s putting out 1800 psi at the nozzles.:flushed:

I have a 8/3500 pump sitting in my garage, just waiting to get it installed.

Don’t sell your 16 incher. I promise you will be disappointed. Just buy a bigger one. I use a 16 inch with my 8gpm every day. I can practically run behind it. You can also wash brick or concrete steps. Which is a huge time saver for entryways to churches or schools.

Don’t forget about slate walkways or uneven brick patios.

Also with your 5.5 you should probably be using a 2 nozzle with 2503s

Hey guys,

So I couldn’t change it to a 16” due to exceeding the days I’ve held it on for. So with what I’ve got at the moment, am I still able to efficiently clean without stripes with a 4000PSI 4GPM, 2 x 25025 nozzle 21” surface cleaner ?

I’ll change from a 3 x nozzle to 2 x nozzles instead.

I’ve acknowledged I need to go at a much slower pace than with a 16”.

If I manage to do a few jobs and get the ball rolling I’ll pursue a 16” SC for the 4GPM in the future.

Thanks gents

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Oh I know, was using two 2503’s on the 16” but it striped like mad and post treating didn’t always fix that. Ironically using the 4 nozzle and slower speed/pressure is practically eliminating the stripes.

That’s because you’re not disturbing the dirt, lol.

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I don’t understand. I just added a 5.5 gpm with 2503s in the 16 inch and it barely leaves any stripes at all.

Maybe your water is softer.

Eh, we have a TDS of around 140.

It’s like…the dirt comes off fine, but where the nozzles track the most on the outside it polishes the concrete more than the middle and leaves these railroad tracks. I was about to try 4503’s until I decided on the 4 nozzle, which works so much better.