So at this point I’m working with an xjet to clean metal roofs/carports, I’m saving up to get a 12V system as I know that’s the proper way to clean roofs. But for the time being, I’m curious about the process for others who use an xjet on metal surfaces. I don’t run a proportioner and usually mix my solution 50/50 with a good amount of elemonator, which I believe should put me around 3-4% sh. To get any decent results I always have to spray 4-5 applications, and I won’t notice a difference until the 3-4 application. Sometimes I’ve even sprayed the mix on there straight without mixing in water and just kept it really wet and even then it still takes sevral applications to see improvement. I know it shouldn’t be this difficult, and I know this is roughly the mix I’m putting out because i use it to post-treat concete and it’s always more than strong enough. So if there’s anyone out there that has success using an xjet to clean metal roofs, please chime in and share your process/advice (besides upgrading to the 12v, I know that’s what I really ought to do) 
If your truly spraying 3-4% sh I don’t believe you need 4-5 passes…you might be spraying a lower % of sh than you realize….
@Kentucky1234 Maybe that’s all it is. I just know it works like it should when I post treat, using the same 50/50 mix with no proportioner. It sure smells strong enough to be at least 3-4% as well. I get sh from a local business that claims it’s 12% chlorine.
I would try straight SH, don’t mix with any water and see if that helps. I think your mix is too weak…3-4% sh should clean pretty well not needing several passes.
At 50-50 you’re probably outputting about 2%…maybe. I remember when using my 4/4 machine it would suck down about a 10-1 ratio with no insert.
What size is your machine?
So if you’re using 12% SH, your ratio at “open” is 2:1 which in fraction form is 1/3. So you’re pulling 4% without watering down your SH beforehand. Watering it down 50/50 brings you down to 2%.
So @Kentucky1234 nailed it. Try it without watering it down.
Try using a scrub brush. One pass and then scrub a bit. MAke sure the brush isnt wiry and hard. a softer bristled one that gets all up in metal roof seams. Shouldnt take very much scrubbing at all but in my experience it definitely speeds up the process and keeps from wasting SH.
@Dallsheep That won’t take off any potential oxidation or UV protective covering? I thought I read that in a thread somewhere.
If it’s chalky already let them know it’s oxidized. I do not restore, just clean the metal roofing of organics. A scrub brush, sh, a little bit of soap, and something to keep you attached to the roof if you fall off of is all you need aside from a thorough rinse to look like this 
I tried multiple applications of SH when I first started and found this, for me, to be the way to go. Now I only apply once, let set, then lightly brush and rinse.
I get my SH from a local distributor and it’s HOTT!!! Stuff ain’t playing I use my xjet bucket with 20ft of 5/8 flex hose and my short one handed gun with my xjet tip low low pressure on my 4.2 gpm predator pressure washer I got from harbor freight and it will throw water no lie 50-55 ft it’s just as good as soft wash plus I can coat a roof in a heart beat
