If you simply do not want to use chemicals to keep your kiddie pool clean, there is an alternative. Rather than chlorine, use Distilled White Vinegar. Add 1/2 Cup for every 100 gallons of water in your pool.
Dirty stagnant water can be a breeding ground for mosquitos, harmful algae, molds, etc. It is very important to drain the kiddie pool completely after every use. Allow it to fully dry under the heat to get rid of any moisture left. For cleaning, you can use bleach or vinegar (diluted in water) to disinfect it.
If your kid's pool is pretty small, and draining and refilling it doesn't feel like a colossal waste of water, then the best way to keep the kiddie pool clean is to drain it when the water's dirty, scrub it down with a plain old kitchen brush and some mild dish soap, and refill it.
Vinegar or Baking Soda
Both are effective and safe, so choose whichever one you have on hand. Dip a sponge into the mixture. Use the wet sponge to wipe down the inside of your drained pool. Scrub away any dirt or grime that appears.
Unlike chlorine, vinegar is non-toxic and can be used to get rid of algae in pools. It also destroys mold, weeds and other microorganisms.
Ordinary household vinegar could in theory be used to lower the pH of your pool. The pH of vinegar is about 2.5, which is quite acidic when compared to your pool water. Household vinegar is very weak though (when compared to a strong acid like muriatic acid), so you would need quite a bit to lower pH.
How To Clean Without Chemicals: For the pool, you see in the picture (this one here) I simply added one cup of distilled white vinegar to it each day. Then I would mix it around with my hand and that is it. The kids would hop in right after not having to worry about chemical burns.
Mix a 50/50 solution of vinegar and water, dip a sponge or soft cloth into it, and scrub that residue away. It's OK if a little bit of it makes it into the pool water, but if you're concerned, test the water after using vinegar, and adjust any levels if necessary.
If you don't have a drain plug in your kiddie pool, but you have a nearby hillside, you could use a garden hose to siphon most of the water out, to a point where you can flip it over to empty fully. An easier method would be to use one of our small submersible pumps.
Salt is often presented as a healthier alternative to adding chlorine to a kiddie pool, since saltwater is gentler on the skin.
Baking soda will raise the total alkalinity of the water. The alkalinity keeps the pH stable which then allows the bleach to remove more bacteria and contaminates. About a 1/2 of a teaspoon of baking soda will treat 26 gallons of water.
A rule of thumb is 1.5 lbs. of baking soda per 10,000 gallons of water will raise alkalinity by about 10 ppm. If your pool's pH tested below 7.2, add 3-4 pounds of baking soda. If you're new to adding pool chemicals, start by adding only one-half or three-fourths of the recommended amount.
Saltwater In An Inflatable Pool
They do make saltwater systems for above ground pools for those who don't want to use chemicals. For example, this Intex Pool Saltwater System found on Amazon. This is a great system for people who want to get rid of all the hassle that comes with using chlorine.
With Chemicals
If your children use the pool on a daily basis, empty the water every month. If your children use the pool infrequently, wait a month and a half to two months before changing the water. To keep your kiddie pool safe you must add three quarters of a cup of borax to the water.
Swimming pool pH reducer is made of granular sodium bisulfate and will act quickly to correct your pool's pH level to re-establish an ideal swimming environment. pH reducer can be used to lower swimming pool pH levels whenever they rise above 7.6 ppm.
Can you swim in a pool with high pH? Definitely, but know that chlorine in the water may not be as effective as it normally would and you may be exposing yourself to harmful microorganisms. Besides, the water can also turn cloudy and your pool sides may scale due to alkaline water.
Most pool experts recommend a pool pH between 7.2 and 7.8. To raise or lower pH, a pool custodian simply adds acids or alkalis into the water. For example, adding sodium carbonate (soda ash) or sodium bicarbonate (baking soda) will generally raise the pH, and adding muriatic acid or sodium bisulfate will lower the pH.
I think the answer to your question is about 3-6 days. The problem is that the chlorine that you need to keep the bacteria in check is used up more quickly as the temperature rises, the activity increases, and as sweat and other body stuff is put into the pool.
Small inflatable or plastic kiddie pools and water slides don't have the same protection against germs that a swimming pool, hot tub, or water playground do. That's because it is unsafe to add germ-killing disinfectants, such as chlorine or bromine, to the water in kiddie pools and water slides.
Do not use Epsom salt in an ordinary, chlorinated pool. Epsom salt will quickly corrode traditional filters and can cause other pool problems that will require the intervention of a professional.
Skimmer Net
With excessive debris in the water like leaves, pine needles, and dirt, the pool walls will get slimy and grow mildew faster.