Eliminating "Racing Stripes"

[Dave W 1]

For a Christmas present, my wife bought me a "pro-sumer" grade pressure washer (Dewalt 4000psi/3.5 gpm rig).  I bought a 16" BE surface cleaner to go with it.  I am looking for advice to get rid of the racing stripes the surface cleaner leaves behind.  I did not use any chemicals on this first try.  A friend of my suggested using pool chlorine/water at a 50/50 mix with a cup of Dawn detergent before washing.  Any tips from the pros to eliminate the stripes?  Am I going too fast with the surface cleaner?  This is central Florida, black algae and grime is what most driveways get dirty with.  Mine is broomed concrete.  

The first 2 pics are before. The last one is after my feeble attempt.

Thanks,

Dave

 

[Beth n Rod 1,279]

We typically apply chems to assist in the cleaning. When we get the remnants of like what you are seeing, simply reapply a 50/50 bleach and water
(or stronger as you deem necessary) to finish cleaning.
If the driveway is as bad as you see, hot water can help as a future consideration. I know your machine is a cold water unit
but just to put it out there that colder temps make for less effective cleaners as well.
Food for thought.

Rod