Mike,
We are a pressure washing service in Oregon also. Glad to see you on. We have done some aggregate concrete with our surface cleaners. We didn't find that we had to go any faster with the machines. We use a chemical line that i would like to talk to you about. We also do heavy equipment, so a heavy duty degreaser is a must. You could personal message me, or give us a call we would like to get aquinted with you, maybe there some things we could help you out with. We are located in the Roseburg area. The answer to your question about downstreaming injector is we have a new set up for applying our chemicals that we would like to share with you. These folks here on The Grime Scene are awesome they have been such a great host of information. Get ahold of us. Maybe we could hook up some time over lunch our treat.
Duner