Fill water to spcified mark on the tube, fill the rest with E85 to the mark shown, mix and let the water absorb into the Ethanol. The gasoline will "Float" and leave a boundry line to tell how much Ethanol is in the fuel.


That would work too.

Do you do this at the gas station or once you get home? If last the gas station, do you have a small 1 gallon jug you pour the fuel into first?

I take a 5 gallon container and fill it with one gallon and test it when I get home.

I also make sure to fill to the meniscus and use distilled water.

Thanks

Good info. I've got one of the testers on order.

I test at the station with a red solo cup and a bottle of distilled water that I fill from jugs at home. It's a 5 minute process or less and is a necessity given how much money we have in our cars.

And thanks Kevin for persuading me to switch. :)

Does distilled water make a big difference? And is there a trick to getting consistent measurements? I'm using the tester mentioned above in the Lethal Performance link. On 3 consecutive tests over a 15-20 minute period, I've gotten 94%, 100%, and 89%. I filled about 1/4 of a 2 gallon gas can over at the Kroger on Old Denton. I brought it home and used tap water from the sink. I'd expect slight variations in consecutive measurements, but these are all over the place.

ok...so I don't know what was up with the first 2 - they were the first 2 times I measured - but I didn't do anything different than the last 3. The last 3, I've gotten 89, 90, and 90. So I'm assuming 90% is accurate.