So I thought it best placed to ask this question here, its a bit of a minefield I know so bear with me. So I bought a Karcher Foam lance today (cheap I know at only £14 so haven't really went for top quality). Now I have BH Auto Foam to use as I used this out of a pump spray as a pre-wash but wanted to try it as a foam. Ive read the good post on DW regarding how to work out how much concentrate to use in the lance bottle and I have a question: Using the calculation on DW, it took 9L of water to empty my lance bottle of 300ml of water (the lance bottle on my Karcher holds 600ml so I just did half). Multiply that by 0.04 (4% PIR) gives me 360ml. Now that means I need to use it neat in the bottle with no dilution, and even then it would give slightly less than 4%. Does this seem feasible and does anyone have any experience? Most things ive read people generally need to dilute the bottle 50/50 give or take. I then thought i'll just try it - so on the wifes car I used it neat - it did seem quite thick but it ran thinish (like reviews said it would), and this was all fine, but then I looked at the bottle and it had used like 150ml of concentrate for a small hatchback, I did not have to spray it very much so this seemed like a large amount. Total head f**K! Maybe with concentrate in the bottle as opposed to water, the pressure washer sucks more out I don't know. Im just confused now. My biggest concern is just using it neat may be way way too strong and I end up doing some damage. Any help greatly appreciated.