20 quarts

Figure about a 75% packing efficiency. Your 55 gallon drum comes to 208 liters, or 208,000 cubic centimeters, or 208,000,000 cubic millimeters. 208,000,000/808.5 gives you 257,612 quarters, but with 75% packing efficiency, only 193,208 quarters will fit in your drum. That comes to $48,302 dollars worth of quarters.

around 35 inches

between 0.9 and 1.5 mm

Remove the lid from the barrel, if possible, to allow access to the inside, and clean the barrel with a solution of 1 to 2 tablespoons of bleach added to 1 gallon of water. If the lid is not removable and you don’t want to cut off the top, fill it about one-fourth full of water and add 1 cup of bleach.

You need to use four and a half cups of bleach for a 55-gallon barrel.

How to Disinfect Water in a 55-Gallon Barrel for Long-Term Storage

1. Add 1/4 teaspoon of calcium hypochlorite to the filled barrel and screw the lid on.
2. Add 2 Tablespoons of FRESH unscented regular bleach (sodium hypochlorite).
3. Add 1 bottle of Water Preserver Concentrate.

Preventing your water tank freezing during cold snaps in winter is an easily preventable task:

1. Use Larger Tanks.
2. Use Round Shaped Tanks.
3. A Sloping Tank Cover Helps.
4. Ensure Proper Tank Insulation.
5. Avoid Insulating the Bottom of the Tank.
6. Use a Water Heating System.
7. Check the Connecting Pipes for Leaks.

It does not freeze and we had 12degrees this winter. Maybe put a insulated hot-water blanket around them. Why don’t you want them to freeze? It shouldn’t hurt them any.

about 3 hours

If left uncirculated, the water at the top of the tank can become stagnant and start freezing. Potable tanks are often equipped with mixing systems that help keep the water circulating and above freezing temperatures. Leaks or overflows in tanks are also likely to cause freezing, especially steady leaks.