I have not read through all the comments so I may be beating a dead horse here but I would recommend a test spot of 50/50 12.5SH and water, 6% is strong but if it works you will know you’re mix is too weak. Also, when downstreaming I would not dilute your SH because your machine will dilute it for you. 10:1 with straight 10%SH will get you at 1% l, if I’m not mistaken and that should be plenty good for vinyl. If you are cleaning brick, don’t even attempt to downstream, you will need a pump sprayer or an xjet. I just purchased my xjet but have yet to use it.
