After reading a recent article on SurvivalBlog about keeping stored water clean, I thought I’d mention my experience with that. While living in the Colorado mountains, my water source was from a short stream running from a spring. This filtered water was pumped into a 1,000-gallon tank in my basement. All surface water is subject to some contamination, but in all the years it was used it never gave me any problems. I finally had it tested, and the bacteria count was some 50 times what was allowed. After that test, I figured I was living on borrowed time and decided to do something about it. After some research and having used it on my hot tub, I decided on an ozone system. The advantage of ozone is there is no chemical added to the water. Ozone is just oxygen with an extra oxygen atom temporarily attached to the normal O2 molecule. This acts like a super oxidizer that kills any living particle it encounters in the water tank. This includes bacteria, viruses, and various spores, like Giardia. Ozone then reverts within a second or two to a normal oxygen molecule and bubbles out of the tank.
The day after installation, a test of my water in the 1,000-gallon tank showed a zero bacteria count. Besides effectiveness and no chemicals added to your water supply, an ozone system is dead easy to build and install. It consists of a box the size of a shoebox with a UV light in it. The UV light generates ozone from the air. A small plastic tube leads from the box to a venturi and the discharge of a submersible pump, the kind used in small water features. Little Giant is one make. The pump is the size of a fist and inexpensive to buy and run. The venturi is a little plastic fitting that costs a couple of dollars. As ozone is safe for fish, aquarium pet stores often carry all this as does Amazon. As the pump circulates water, it pulls air from the light box, bringing ozone with it. Here are a couple of cautions:
- The time of ozone contact with the water is crucial so this system works with unpressurized tanks and not inline pipes.
- Using it just when filling a tank or leaving the water sit for years won’t work well either. There is no residual chemical to clean any water added after the system is shut off. That water will not be cleaned.
- If your tank continually fills and empties, like a my cistern, the ozone needs to run continuously. Obviously, this system uses electricity, although very little.
- If you simply store water, then a periodic run would suffice. Your water management after SHFT would have to take this into account.
- Ozone as mentioned is a very good oxidizer and will rust any metal near the tank Things like metal shelves, tools, or guns should be kept in another room.
- Any ozone that escapes your tank will also kill fungus and mold in and around the tank, which is good but sleeping in the same room might not be a great idea.
Other than that I can’t think of why anyone would not use ozone. – Expat