Perfect, PERFECT. Now, you can do a show and tell.
First thing is to strip it down. It all comes apart really easy. The insulation may be stuck to the tank, but, it's not a problem. Do NOT remove any E parts.
Once stripped down, look for a "track" where the leak ?? might be coming from. Usually, a leak will be in the seam, where a dab of flux from welding, has plugged a pin hole. Later on, it just can't hold pressure. I have done over 2 dozen of these tanks. Most had the same problem leak, but not all. If it is in the side or bottom, a gooped up sheet metal screw will work fine. Of course a Mig welder will do you just fine, also, BUT, you could damage the epoxy-glass lining inside the tank, so, think before you act.
If you can find a leak, hook a garden hose to the inlet and fill the tank. THEN, cap off the outlet and let the house pressure pressurize the tank. IF it eventually leaks, you get a fine mist or pisser. DO NOT pressurize with air. IF it blows, you COULD have consequences. Tanks are filled with water to test them, so they do not blow. PERIOD.
If there is no leak, you are golden.
Scrounge around for a standard glass sliding door. It is perfect for a solar "Breadbox". While looking and asking around, open or remove the bottom drain pipe, so you can use a wire coat hanger, or, cut a piece of E conduit, on a long sloping cut, to use as a scoop and scrape out the lime deposit from heating the water. You MIGHT be lucky and only have a small or no buildup. This is why E heaters go bad. The lime from the water gets deposited on the elements and they can not get water cooled, so they burn out. They also get to slough off some of the lime coating on the element, until you get a large deposit build up in the tank, which will insulate the lower element and cause IT to burn out.
You will need to run a hose to one upper nipple, to flush the crap out the bottom hole. That's why it might be better to remove that drain pipe.
After the tank is clean and leak free, check continuity on both elements, to see if they are shorted-grounded to the tank. If not, you are more golden. Leave all the E hookup in place. You can use it later, if needed, on rainy ?? days. You lay the tank on it's side, with the elements on the bottom side. When you hook up the tank, the elements work just as well as upright tank. THIS DOES WORK. I have built more than 6 horizontal systems, and hung the tank between the floor joints in the basement of houses.
IF an element is bad, buy a new one, that is DOUBLED BACK on itself. It will look like someone has taken the long loop and bent it in half. This is even better than the straight type. It's shorter, so, it works equally as well in a horizontal system.
Now, you can scrounge pieces of 2 X 4 to build a box. If you have other ideas, that's fine. If you want to build the breadbox design. Let me know if you want some ideas.
The most important thing is to keep the tank lower than your other tank, inside the house, so hot water can rise and heat the water inside the house, as you are not using hot water, or, you need to plumb a hot water pump into the system.