Wow! And all I was trying to do was determine if the chlorine in the jug had degraded significantly!

The measure of 1.88ml/5gal can also be done in metric: 1ml/10liters--5 2 liter soda jugs.

Metric vs English (Imperial implies Imperial gallons)?

It's a mistake to say we abandoned the Metric system as too hard. It's creeping up on us in many ways. If you work on cars or motorcycles, almost all the wrenches you will use will be metric. 20 years ago I had no idea what a 12 mm wrench was, vs a 17mm. Today an image pops into my head automatically. Soda is sold in 2 liter jugs, 1 liter jugs and even 3 liter jugs. ALL medications are administered in metric measures and only sometimes, for liquids (like cough medicine) is there a teaspoon equiv. You can even use the bleach calculator formulae in metric: Just measure your pool in liters and your bleach in liters and it works out the same.

In the UK, they thankfully STILL keep one imperial measure--the British Pint! They also, curiously measure body weight in Stone, rather than pounds or kilos.