How to keep the pool water clean without nasty chemicals

CYA can be higher than 20-40 without any problems. I'd say it only become a problem when you start going over 100. It's true that you can't get rid of it without partially draining your pool, though.

Your CYA should be ~40ppm, so once you figure out what it is, adjust it as necessary, partially draining and refilling the pool to lower it, or adding CYA to increase it. (I haven't used a taylor test kit in probably 10 years :S Are you sure it's really 300 ppm? If so, I'd pretty much drain the entire pool... lol.) CYA keeps the chlorine from evaporating off and is very important, but having too much CYA makes the chlorine ineffective. Once you get your pool to ~40 ppm CYA, add bleach at night (to help prevent evaporation) with the pump running.

If you find that you are still unable to hold FC even with a good amount of CYA, then you have "chlorine lock," which is a situation where, when you add chlorine, it combines with something (typically ammonia or urea, created typically by not maintaining proper chemistry, at which point your chlorine evaporates, followed by microorganisms eating your CYA, turning it into ammonia and urea) very quickly. Some people out there kick and scream when they hear the words "chlorine lock," even though they do not question that there are situations in which free chlorine will be gobbled up very quickly. They hate the term because they hate the pool chemical industry / pool maintenance companies, but pretty much everyone agrees on the solution, and it's very simple: you need to add a large amount of chlorine into your pool, whether it be chlorine shock (that does not contain CYA) or liquid chlorine bleach. When you have chlorine lock (i.e. an ammonia/urea problem,) adding a half-gallon of bleach is like attacking a ten-acre fire with a garden hose. It's the right idea, but not on the correct scale.

Here's how to fix the problem:

1. Dilute a small amount of your 10% chlorine bleach -- three parts water, one part bleach. For example, 1 fl oz bleach, 3 fl oz water.
2. Get three one-gallon buckets and put one teaspoon of the diluted mixture into the first bucket, two teaspoons into the second bucket, and three teaspoons into the third bucket.
3. Add a gallon of pool water to each bucket, stir gently, and put the buckets in the shade for 4 hours.
4. Test the chlorine levels of the buckets after 4 hours. Whichever one has 2-3 ppm of chlorine left, is the one you want to do your math on. If none of them have 2-3 ppm left, add 3 teaspoons to each bucket, stir gently, put the buckets in the shade for 4 hours, and test again -- repeat the process until you reach 2-3 ppm.
5. Take however many teaspoons you added into the bucket that read 2-3 ppm, and multiply that number (1, 2, 3, etc.) by 4.5 (math below), giving you how many gallons you should add into your pool to fix the problem. Add the bleach at night, with the pool pump running.

1 diluted tsp / 1 gal pool water = 15,500 diluted tsp / 15,500 gal pool water

15,500 diluted tsp / 768 tsp/gal = 20 diluted gal

20 diluted gal = 5 full-strength gal

Use 4.5 instead of 5 to be on the safe side. This likely won't be quite enough, so if you find that your pool is still unable to hold any FC, add 1/4th of a gallon of bleach each night until it starts holding some FC.

In my experience, most horror stories of pool maintenance are usually the result of neglect, or not paying attention to the instructions. It's not that hard, but expect to spend an average of 10-15min per day checking on your pool, adding chlorine, clearing out leaves in the skimmer, etc. Also, once a week, expect to spend some extra time brushing/vacuuming the pool and cleaning the filter.

As a first time pool owner, the simplest thing you can do is pick up a free pamphlet on pool care. Follow the instructions in the pamphlet, and make sure you stay on top of it. My Wal-Mart usually has pamphlets by HTH Pools next to their chemicals.

Start by getting a test strip kit. You dip the strip in the water and compare the colored pads against a chart. Pretty easy (unless you get into a fight with your wife about the shade of orange of the pH pad).

Make sure you pick a good test kit, which measures several properties of the water (should measure pH, stabilizer/CYA, alkalinity, hardness, chlorine). Cheaper ones will only measure a few properties.

Measure your pool every day or so. If the levels are off, adjust them by adding the appropriate chemicals. Just follow the instructions on the container. Most any chemical you need can be found at your local pool store, or Wal-Mart. Beyond that, I'm not going to repeat what you would find in the pamphlet. (Did you get one yet?)

One bit of advice that wasn't in a pamphlet: If you buy "stabilized" chlorine products, they will raise the level of stabilizer/CYA in the pool. If your CYA levels are already high enough, the stabilized product can push your levels over the top. If you aren't sure if the product is stabilized, look for the words Dichlor or Trichlor in the ingredients. Un-stabilized chlorine is usually Calcium Hypochlorite or Sodium Hypochlorite.

Beyond the chemicals, there will be some "mechanical" maintenance/care:

• Dirt, pollen, and algae will naturally collect in all the crevices of your pool, so use a pool brush to break it up. Regular churning of the water (from brushing or swimming) will give the filter an opportunity to suck up the debris before it settles.

• You will need a vacuum (manual or automatic) to suck up non-floating debris. 48 hours before vacuuming, shock the pool to make sure any algae is dead. 24 hours before vacuuming, add some clarifier to make the algae and dirt settle on the bottom (where the vac will get it).

• Make sure your filter is clean. There should be a pressure gauge on the filter that will indicate when too much crud has built up in it (pressure levels will go up). At that point, you need to clean it. Some filters are cleaned by backwashing. Others have a cartridge that needs to be changed. The filter should come with some instructions on how to care for it.

• Check the strainer baskets in your skimmer and pool pump. Larger debris like leaves and large bugs will collect there. Periodically shut off your pump and scoop the crap out.

• A plugged filter or strainer basket will strain your pump, and maybe cause a burst hose (very bad). So, keep the water path clear.

• If you have cold winters, make sure you follow the instructions on winterizing the equipment. I disconnect my pump and bring it indoors every year.