R.,
It sounds like we have similar size "temporary" pools. Our is 13 feet and 39 inches deep. We just put our's up last Sunday night. It's amazing it only took four hours to fill yours up because it took from 9:30 Sunday night until 5:00 Monday morning to get the nearly 3000 gallons of water into ours.
Anyway, to answer your question about water maintenance. I'm assuming that you've bought one with the pool pump and filter? If so, you need to check the manufacturer's suggestion for chlorine. Ours very clearly on the box said to use 1 inch chlorine tablets that go directly into the top of the pump where the filter is. You will also need to maintain the Ph level and it is best to shock the pool one every week or so to keep out bacteria. You should buy a water test kit and test daily so you know how much of what to put in the pool. If the Ph is too high then you'll need to put in a Ph Minus, if it is to low, then you'll need to put in a Ph Plus. Again, you'll need to buy the Chlorine to add in daily (I've figured out that 3 tablets a day will keep ours okay)and then the Shock Powder to do initially and once a week. Also, buy a skimmer net so you can fish out leaves and bugs. We have been covering ours at the end of each day so I would suggest that, too so you don't get tons of pollen, dust, bugs and leaves in the pool. Remember, the more the water is subjected to sunlight and people, the faster the cholorine will be used up so it is very important to check it daily to prevent bacteria that could make swimmers sick.
Toys R Us has a great supply of chemicals and each bottle has excellent directions on proper use so if you have one nearby, that is a great place to start. I'm a beginner with this, too but if I can add anything else to help you guys out, please let me know.
Happy Swimming!
