I have noticed, especially when using Bio-Pro and citrus solvents, that using the yellow metering tip in an HF sprayer is just not accurate. I haven't accurately measured it yet, but I can tell that it is not as good as going without the metering tips. When I remove the tip, I can pre-spray about 3 large rooms @ 4/1. Whenever I have the 8/1 tip in, it seems like I can do like 12 rooms before needing to refill. And sometimes when I have a metering tip in, it seems like the prespray is cooking. Almots like it is getting clogged and getting too hot and shooting out steam or something, it is very strange. Never ever happens whenever I have the tip removed. And I KNOW I am getting the same dilution everytime. I just thought I would post this to suggest changing your sprayers to 4/1 instead of 8/1, as I now think it is a better, drier way to clean. Anyone else notice this as well?