Guide for Seasonal/Temporary Pools
This guide covers smaller pools that have a pump and filter and which get completely drained and put away each winter. Water chemistry for small pools follows the same basic premise as it does for large pools: maintaining a minimum level of chlorine for sanitation and algae prevention, and protecting chlorine from rapid degradation from sunlight buy using a chlorine stabilizer. There are numerous components to pool water chemistry; this document provides only the most basic outline to maintain clear, sanitized water.
A few things to always remember
Maintaining clean, sanitized, water requires a few minutes of daily testing and adjustment. Get into the habit of checking the pool every day right from the beginning.
All chemical additions should be made while the pump is running.
Filters for these pools are disposable . . . stock up on them. Plan to change them every couple of weeks as recommended by your pool documentation, and more frequently if problems arise.
Chlorine levels drop somewhat during the day due to sunlight. Chlorine levels also drop when in the presence of organic materials (algae, bacteria, etc.) that appear in the water (in other words, as chlorine does it's job, it is used up). How rapidly chlorine levels drop depends on several factors - two important ones are how much stabilizer (CYA) is present and how many people are using the pool. Think of CYA as "sunscreen" for chlorine.
Test your fill water. For this you need a drop based test kit that tests for at least pH and chlorine. No strips - they aren't accurate. The test kit will also reference bromine along with the chlorine, but ignore that. Write down your pH level . . . you're aiming for something between 7.2-7.8. You probably won't have a chlorine level. Get into the habit of testing your water for pH and chlorine every day - it takes only a couple of minutes and is the key to clear, sanitized water.
Calculate how much water your pool holds (PoolMath). Your instruction manual might tell you this. For Intex easy-set pools (the ones with the blue inflatable ring), PoolMath doesn't work as accurately due to the sloping side walls of the easy-set style. Use the information on Intex's website here: http://www.intexcorp.com/faq/3307.pdf.
Use PoolMath to calculate how much bleach you need to raise your chlorine level to 6 ppm. Also use PoolMath to determine what you need to do to change pH if necessary (if it's not in the good range of 7.2-7.8). Directions for PoolMath are here: http://www.troublefreepool.com/pool-school/pool_calculator.
Based on your fill water test results, the size pool you have, and PoolMath, plan what you need to buy:
--Bleach - label should say sodium hypochlorite 6% - sometimes called "ultra", with no added scent. Check the percentage, it sometimes comes at lesser concentrations. Bleach will be your daily chlorine source to sanitize your water. Chlorine is quickly degraded by sunlight, so you'll also use a stabilizing product (CYA), explained below (see Dichlor).
--If you need to raise pH, buy Borax (in the laundry aisle . . . "20 Mule Team" in a green box is a common brand)
--If you need to lower pH, buy dry acid, also called PH Down, Lo 'N Slo, PH Decreaser, etc.
--Polyquat 60 algaecide . . . poly [oxyethylene (dimethyliminio) ethylene (dimethyliminio) ethylene dichloride 60%. Do not buy an algaecide with copper as an ingredient . . . copper is what turns things green. Algaecides help prevent algae growth.
--Dichlor - chemical name is dichloro-s-triazinetrione, also called "pool shock". It frequently comes in small bags. Purchase approximately one pound for each 2,000 gallons, or fraction, of pool water. Dichlor adds both chlorine and CYA (stabilizer . . . "sunscreen" for chlorine). You will only use it for a few days, so don't buy more than what you need.
Step 5 - the first four days
The first few days will be spent using dichlor to add chlorine while also raising your CYA level to help protect the chlorine from the degrading effects of sunlight. If you want to be able to jump into the pool as soon as it's full, use PoolMath to determine the amount of bleach needed to raise your chlorine level to 6 ppm. Add that amount of bleach while the pump is running. Wait an hour to let it circulate before you use the pool.
The first four days, you will use dichlor to both chlorinate your pool and raise the level of CYA (chlorine stabilizer). The first evening, after you're finished swimming, turn the pump back on, test and make any adjustments to pH. Let the pump circulate any chemicals added to adjust pH (30 minutes or so) and then add one ounce of dichlor for every 500 gallons of water. To add the dichlor, add it first to a bucket of pool water and let it dissolve, and then dump that into your pool. Let the pump run overnight. This dichlor addition will raise the chlorine level to about 8 (assuming no chlorine was added prior . . . if it was, the chlorine level will be a little higher, which is fine), and the CYA level to 8.
Repeat the above procedure each evening for four nights total. At the end of four nights, your CYA level should be around 30, right where it should be. After four evenings of adding dichlor, STOP USING THE DICHLOR. This is really important, even if you have extra left over. There is a complex relationship between chlorine and CYA, and too much CYA is absolutely not a good thing.
Each evening, continue to test your pH and chlorine, and make adjustments as necessary to maintain both.
Step 6 - daily pool maintenance
Continue testing your water each evening for pH and chlorine. Now that you aren't using dichlor, bleach is your daily chlorine source. Try not to let your chlorine level fall below 2. If the chlorine level is above 2 then add enough chlorine to reach a target FC level of 4. If 2 or lower, raise FC up to 6. Chlorine is best added in the evening to protect it from sunlight for as long as possible. Also, make any adjustments necessary to keep pH in a range of 7.2-7.8 and chlorine above 2.
Step 7 - weekly maintenance
Following the directions, add the recommended amount of Polyquat 60 once a week throughout the swimming season. This will help prevent algae outbreaks, which can be very difficult to clear using the pump/filter supplied with these smaller pools.
--Chlorine drops too low
If your chlorine drops to zero, plan to SLAM your pool using bleach. Calculate how much bleach you need to raise your chlorine level to 12 and add that much in the evening.
--Can't find dichlor at the store
You have two choices:
1. Use PoolMath to determine how much CYA you need to raise your level from 0 to 30 for your pool size in gallons, and purchase it separately. Know that unless you find a small quantity, you won't use everything in the container (remember that too much CYA is a very bad thing). To add CYA (not dichlor), put it in a sock, tie a knot at the top of the sock and either a) drop it into the skimmer basket and let it dissolve slowly (takes about a week) or b) tie the sock off to a ladder, etc. (ideally near the return) to suspend it in the water until it's dissolved. Do not broadcast the CYA into the pool and let it settle to the bottom; that is hard on the vinyl.
2. forgo CYA altogether (we don't recommend this, but if you truly can't find it, this is your option) and be diligent about maintaining chlorine levels. This will be tougher, and you will likely need to add chlorine before swimming to reach the minimum target level of 2, especially late in the afternoon, as unprotected chlorine is consumed quickly in sunlight.
--Pool water starts to turn cloudy or greenish, pool surfaces feel slippery
If the water begins turn cloudy or greenish, or pool the surfaces becomes slippery an algae bloom is likely starting to take hold. It is difficult (but not impossible) to resolve an algae bloom with the equipment included in these types of pools. Often, the easiest and quickest solution is to drain the pool, scrub the sides and bottom thoroughly, and start over. If you choose that route, start over with the water chemistry just as you did the first time.
If draining the pool doesn't appeal to you, you need to plan on investing in a top-quality test kit (see this article at pool school for comparisons of the three test kits TFP recommends) -- all three are generally only available on-line so you'll need to plan a couple of days for shipping. Come back to the forum, read pool school two or three times, and post your questions. We'll help you out. If a top-quality test kit isn't an option, your best best is to drain the pool. We won't be able to do much for you without the information the advanced test kits provide.
The pH and chlorine test kit is the very, very basic necessity. If you want to learn more about your water chemistry, and/or you're using this small pool as a "starter pool" before jumping into a more permanent pool, consider a more advanced test kit. A good intermediate test kit is the HTH 6-way test available at WalMart. In addition to chlorine and pH, it tests total alkalinity, calcium hardness, and CYA (enough for two tests). Recommendations for the best option in test kits can be found in this article at pool school.
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