Pool Maintenance

Proper water balance is the single most important factor to maximizing the life and appearance of any swimming pool. The following table shows ranges for basic water chemistry.


free chlorine
Total Alkalinity
Calcium Hardness

80-120 ppm
200-300 ppm
35-60 ppm

test frequency

*end table*

pH Levels

pH is the measurement of acidity of water, which is measured on a scale of 0 to 14 with 7 being neutral. A pH below 7.0 means the water is very acidic, as the pH approaches 8.0, the water becomes very basic (alkaline).

Not only do proper pH levels allow the other chemicals to do their work, but it is important to note that low and high levels can cause damage to a vinyl liner. Under the right circumstances with pH below 7.0, the liner can actually grow and develop unsightly wrinkles. High pH greatly accelerates the aging process and shortens the life of the liner.

Chlorine is much less effective at higher pH levels. Eat a pH of 8.0, chlorine is only 22% effective.

Total Alkalinity

Alkalinity is a measuring of the alkaline materials dissolved in water. With the alkalinity in the range of 100 to 150 PPM it helps pH to resist fluctuations. If the alkalinity is low the result is “pH bounce” in and out of range.

Calcium Hardness

Calcium hardness refers to the amount of dissolved minerals in water. A low hardness can lead to corrosion of pool surface, filter, heater, ladder, etc. A calcium hardness level that is too high causes cloudy water and scaling (white chalky appearance).

Out of Balance Water

Eye and skin irritation
Unsightly wrinkles in vinyl liners
Interferes with the efficiency of sanitizers
Corrosion of metals (pump seals, heaters, lights, etc.)
Cloudy water
Scale build up (white chalky appearance) on pool surface as well as inside filter and heater
Pitting and corrosion of gunite/concrete pools

Cloudy Water

The murky, dull appearance of cloudy water can leave the pool looking uninviting. Cloudy water may also harbor contaminants and stain-makers.

Causes of Cloudy Water

Contaminants buildup: When swimmer wastes and other contaminants build up, the result is “combined chlorine.” Shock the pool!

Chemical residue: using a calcium hypochlorite shock such as Shock, Sock-It, Shock-it, Burn Out, or Break Out can result in a residue build up and cloudy water. If the water looks like chalk or milk, it is usually the result of using a lot of calcium hypochlorite shock. To use this type of shock, especially in vinyl liner pools to prevent bleaching of the liner, you must:

Fill a bucket about 1/2 full of water
Add shock. Do not stir. Let sit for a few minutes. Pour only the liquid into the pool.
Discard the residue
Do not try to dissolve the residue

Water Out of Balance: A high pH, high total alkaline, or high calcium hardness will cause cloudy water. Test the water!

Algae: Algae is a possible cause of cloudy water.

Poor Filtration: Is the filter system running a significant number of hours every day? During the swim season, the filter needs to run a minimum of 10 to 12 hours daily.

Pools with cloudy water or algae:
Adjust pH to 7.2 -7.6
Add algaecide 60
Add shock
Add Hydrofloc
Add Majestic Blue
Run filter 1 hour, turn off and leave off overnight
Next day: vacuum the waste

Metals: The presence of metals in the water such as iron (reddish-brown), copper (blue-green) or manganese (brown-red) can cause cloudy water. To remove the metals:
Add 1 quart Hydrofloc
Add 1 quart Majestic Blue
Run filter 1 hour, turn off overnight
Vacuum the waste
When pool is completely clear, add Keetrol (stain and scale preventer) to remove any stains
Use Keetrol weekly to prevent recurrence

Adding Water Balance Adjustment Chemicals
It is best to predissolve a water balance adjustment chemical in a plastic bucket of pool water. Then add to the deep end of the pool or in front of a return with the pump running.
pH Adjustment: Add recommended dosage, wait several hours and test water again.
Alkalinity: Add at the rate of 5 lbs or less; wait about 10 minutes between each 5 lbs.
Hardness: Add at the rate of 5 lbs. Or less; wait 30 minutes between each 5. If large amounts of calcium are needed, add over several days.

Low pH and High Alkalinity …………………….. Adjust Alk first – Next Day pH
High pH Low Alkalinity …………………….. Adjust pH first – Next Day Alk
Low pH and Low Alkalinity …………………….. Adjust pH first – Next Day Alk
High pH High Alkalinity …………………….. Adjust Alk first – Next Day pH

Chlorine Stabilizer (100% Cyanuric Acid)
Stabilizer acts as a sun shield to extend the life of chlorine up to 3 1/2 times. It actually holds the useful form of chlorine in the pool water until needed giving longer protection against bacteria and algae. It leaves no residue; it is 100% soluble. “Stabilized” chlorine products (sticks, tablets, and chlorine powder) contain some cyanuric acid which helps to maintain the proper level throughout the season.

Adding Stabilizer
With a clean pool, backwash the filter. Make a slurry of stabilizer and water, then add very slowly through the skimmer with the pump running continuously for at least 48 hours. Do not backwash for 3 or 4 days after adding stabilizer.

Pool Maintenance

Testing the Water

Follow test kit instructions (test strips are easier to use than kits)
Use fresh reagents–the shelf life for liquid reagents is only one year
Rinse out test cell with pool water before using.
Retrieve water sample at elbow depth from deep end of the pool
Most Important Pool Side Tests: Free chlorine, pH, and total alkalinity. Free chlorine is the unused, effective chlorine that you want in your pool. There are a number of influences can bring out rapid shifts in a pool’s pH. These include:
Swimmer wastes
Refill water
pH of various pool chemicals
CAL HYPO – pH 11.7


Mustard Algae: Common algae in pools appears yellow-brown or “mustard” colored. It brushes off the walls of the pools easily, but quickly returns. It often rows in shady areas with poor circulation. It resists chlorine and shock treatment.

Solution: Use Yellow X along with chlorine shock. Follow label directions. Place all vacuum equipment (hose, head, pole, brushes, etc.) into pool during treatment. Maintain a higher than normal chlorine reading for 4 to 5 days after treatment.

Green Algae: Green algae is one of the most common problems for pools. It usually appears in corners or other areas where circulation is poor. Once established, green algae can grow explosively.

Solution: Use Algaecide 60, Algaecide 50, QLF Algaecide, or Copper Algaecide along with shock and Majestic Blue. Follow label directions. Yellow X along with chlorine shock could also be used in the place of algaecide. It is also recommended to use Hydrofloc, and to always vacuum to waste or drain (not backwash).

Black Algae is a very resistant form of algae that clings to the pool’s walls, floor, and cracks. The longer black algae is present, the longer it will take to get rid of it. Black algae can actually pit the marcite finish in a gunite pool. Treat black algae as soon as it is detected. Black algae is usually found in gunite/concrete pools.

Solution: Brush algae spots vigorously with a stiff algae brush and pour Algaecide 60 along the sides where spots are visible. Run filter continuously for one hour, then add chlorine powder, pouring on the spots along the side of the pool. Majestic Blue can also be added to improve water clarity. Turn off filter and leave off for several days.

Preventing Algae

WEEKLY ……………………. Brush walls and pool floor
WEEKLY ……………………. Vacuum pool
WEEKLY ……………………. Use a maintenance dose of algaecide
WEEKLY ……………………. Use a maintenance dose of Majestic Blue
DAILY ……………………. Maintain a proper chlorine reading
WEEKLY ……………………. Keep properly balanced–recommended readings: Free chlorine: 1.0-2.0, pH: 7.2-7.6, total alkalinity: 80-120 ppm, hardness: 200-300 ppm, stabilizer: 35-60 ppm


Turn pump off. Make sure that your skimmer and pump strainer baskets are clean.

Adjust skimmer flaps (located underneath each skimmer basket). Open the flap in the skimmer closest to the pump and filter all the way, and close the other skimmer(s) flap(s). You will vacuum though the skimmer closest to the pump and filter.

If you have a main drain, it should be closed to afford maximum suction through the skimmer. Turn your Jandy valve to shut off the main drain. Turn on your pump and check your skimmer for water movement to ensure strong suction.

Stretch out your vacuum hose along the side of your pool. Snap the vacuum head into the end of the vacuum pole. Slip one end of the vacuum hose onto the vacuum head. If you have a swivel cuff on your vacuum hose, make sure the swivel end goes onto the vacuum head.

Prime the hose. Place the vacuum head (with the hose and pole attached into the pool. Place the hose end (you have in your hand), against the return fitting and allow the water to “blowout” or displace the air in the vacuum hose. The vacuum head will rise and bubble. When it has settled to the bottom of the pool, cup your hand over the vacuum hose and carry it to the skimmer closest to the pump and filter.

Place the skim vacuum plate (looks like a white bowl with a fitting on top) on the end of the hose. Bring the hose over the coping and place it directly on the skimmer basket. Move the vacuum head slowly. If the vacuum head is moved too rapidly it will stir up sediment and your results will be less than satisfactory when the dirt has settled requiring a second vacuum.

When completed, disconnect, remove and drain hose then store. Return skimmer flaps and valves to their normal operating positions. Check filter pressure gauge to see if the filter needs to be backwashed.

Helpful Hints:

Do not lift the vacuum head out of the water or you will lose your prime.
Disregard your filter pressure reading it usually drops while vacuuming.
Disregard air in your pump basket.
Check skimmer basket periodically if the pool has a lot of leaves or other debris in it.
Backwash the filter if the pool is very dirty, and emptying the skimmer basket does not restore suction.
If suction is too strong, open the other skimmer flap 1/8 of the way.


Backwash once a month regardless of pressure. However, if your pressure gauge indicates a high reading, (approximately 10 P.S.I. over your normal reading), backwash immediately. The longer you wait, the harder the dirty DE powder becomes, the more difficult it is to get out of the grids and tank.

Unroll your blue backwash hose to the area you want the dirty DE powder to go or unscrew your drain cap You will lose about fifty gallons of water to backwash.

Turn off your pump.

Turn your multiport valve to the backwash position. Turn on the pump. Watch the blue backwash hose to ensure that it does not kink, or worse, explode! Watch the sight glass on the multiport valve; you will see dirty DE powder running out of the system, after the water has run clear, shut off the pump.

Turn your multiport valve to the rinse position. Turn on the pump. Rinse the tank for ten seconds. This will dislodge any DE that is stuck in the corners and crannies in your filter tank. Turn off the pump.

Repeat steps 4 and 5.

After the final rinse, turn your multiport to the filter position. It’s time to replace the DE that you have just backwashed out of your filter. This is added into the closest skimmer to the filter with the pump running. Add 4 1/2 scoops of DE powder to a 36 square foot filter, 5 scoops to a 48 square foot filter, or 6 scoops to a 60 square foot filter. If using a one pound coffee can, add an additional scoop.

That completes the backwashing procedure. Mark your calendar and be sure to backwash once a month to ensure crystal clear water!

For sand filters, the procedure is the same, with the exception of the addition of DE to your skimmers!
Filter Operation
Skimmer Water Level – Ensure that the pool’s water level is halfway up the skimmer faceplate. This is the normal operating level, (even with the third screw on the faceplate as you count from the bottom up).

Skimmer Basket/Throat – Keep the skimmer basket clean and make sure the skimmer throat is not obstructed.

Pump Strainer – Open pump to ascertain basket is clean, intact and seated properly. Never operate your pump without water or the strainer basket in the pump. Before closing, fill the pump housing with water. Replace the housing cover, making sure the gasket is in position so no dirt or grit will prevent a tight seal.

Filter Pressure Gauge – When starting the pump, it may take a short time for the filter pressure to normalize due to the presence of air in the suction lines. By opening the air bleeder valve located on the top of your filter to expel the air more rapidly. When the air has been expelled, the pressure gauge reading should be 10-15 psi on most filters (15-20 psi on systems with heaters).

Diatomaceous Earth Filters – Do not operate your DE filter longer than one minute without adding DE. Add DE to either skimmer once the water comes out of the returns in a steady stream. Add the DE slowly to the skimmer, or premix the DE in a bucket of water and then add it to the skimmer.
Five Steps to Cleaning a Pool

Test your pool water twice a week. If your water test indicates a low chlorine level, turn up your chlorinator. If your test indicates a high chlorine level, lower your chlorinator. Bather load, rainfall,
and sun exposure will affect the amount of chlorine your pool will require.

Tabs – Fill your chlorinator with 3 inch tabs on the same day each week. Most pools require 5-7 tabs depending on size of pool. Do not exceed 7 tabs unless specifically directed to do so. Chlorine tabs dissolve like bars of soap, do not wait until there are none left in your chlorinator.

Shock your pool at least once a week, twice per week when it is very hot or the bather load is high. You should add 1/2 a pound of lithium hypochlorite shock, for every 10,000 gallons of pool water or liquid shock as directed. You should only shock your pool in the evening, as the sun burns off the chlorine.

Algaecide should be added once per week as a preventative measure. Use 5 ounces of 30% algaecide per ten thousand gallons of pool water. It is less expensive to add this product weekly, then it is to clear up a green pool when it occurs.

pH needs to be checked twice a week and maintained within 7.2 to 7.6 on your test strip. If your total alkalinity is not above 100 PPM your pH will have a tendency to drift, so always adjust total alkalinity first then retest and adjust pH if needed.

We suggest that you have your pool water tested professionally twice per month and immediately after opening, and prior to closing your pool. Preventative maintenance costs less than clearing up your pool after it has turned green!
Frequently Asked Questions

Why do I need to shock my pool every week?

Shocking your swimming pool is a very important element in maintaining your pool water’s clarity and balance. Using chlorine tablets alone will not kill off all bacteria and algae that grow in the pool water. Also, the chlorine tablets have a very low pH level, and their overuse will lead to a low pH, which is very dangerous to the pool, and its users. By shocking the pool each week, you will be quickly raising the chlorine level, which will rid the pool of contaminants, without lowering the pH of the pool water.

Why is the pH of the water so important?

pH is the measure of acidity in the pool water. pH only ranges between 0 – 14, so even a slight change in the pH of your water can greatly affect various elements in your pool. A pool’s pH should be maintained between 7.2 and 7.6. A low pH means that the water is acidic and will dry out your liner, eat away at any stainless steel and copper parts of your pool, as well as cause irritation to swimmer’s eyes and skin. pH can be easily tested for and is inexpensive to adjust.

Why do I need to backwash?

Backwashing your filter removes debris that gets caught up in your sand or DE so that your filter can continue to work effectively in cleaning your pool. Backwashing should be done whenever the filter pressure increases approximately 10 psi over normal pressure, and the water pressure returning to the pool decreases. Follow your filter system’s instructions or contact True Blue for directions on backwashing for the system that you have.

I have a sand filter. Why is my pool always cloudy?

Sand filters have a difficult time filtering out very small debris because often times the microscopic particles of dead algae and waste are smaller than the grains of sand themselves. A sand filter can also “channel,” causing pockets in the filter where water passes through easily, without going through sand. To prevent this, you need to chemically clean your sand at the end of each season with a designated filter cleaner, backwash frequently throughout the season, and use clarifiers to help the water remain crystal clear.

How many tablets should I use in my pool?

We recommend that 1-2 tablets be used for every 10,000 gallons of pool water. During cooler water temperatures and when the pool receives less use, one tablet per 10,000 is sufficient. During the hottest summer months when pool use is high, 2 tablets can be used for every 10,000, but no more then that should be used. Keep in mind that tablets do have a low pH, so overuse of them can disrupt balancing chemical levels. If there is a large amount of algae in the pool, extra shock can always be added without effecting the pH level.

When is the best time to shock my pool?

You should always shock your pool in the evening, after the sun has gone down. Shock is an unstabilized chlorine that can burn off easily from sunlight, even on overcast days. By shocking at night, you are giving the chlorine a chance to bond with the chlorine stabilizer so that by the time the sun comes out the next day, your chlorine level won’t dissipate as quickly. Also, this gives the pool enough time to react with the high level of chlorine, so that you can usually swim the next day after a pool has been shocked.

How long should I wait to swim after adding chemicals?

Most balancing chemicals, such as pH, alkalinity, and calcium hardness, will become incorporated into the water within an hour of adding them, at which time swimming is safe. Shock takes longer to adjust with the pool water, so waiting overnight after shocking before you swim is recommended.

Why do I need to have my water tested professionally every 2-4 weeks?

Testing at home with your strips or drop test kits give you only a limited reading of your balancing chemical levels of your pool water. The average home test kit only reads pH, chlorine, and sometimes alkalinity. There are various other levels that are important to your pool that need to be tested on a regular basis to ensure water balance and safety for the swimmers. Also, the professional testing done in store is far more accurate than home tests, leaving you with added security that your pool water is safe and balanced.

I’ll be going on vacation for a week. What should I do to keep my pool healthy while I am gone?

While you are away, it is important that your water circulates and is sanitized. A pump timer and automatic chlorinator are the most foolproof ways of ensuring that this is done, because they will automatically turn your pool on and off each day, and distribute chlorine into your water. If a timer and automatic chlorinator are not an option for you, having a neighbor stop by once every day or two to run the pump and check on chemicals will help to keep your water healthy while you are away.

What is the difference between HTH and other chlorines?

HTH is a calcium based product, which means that although it can be very effective in killing off contaminants in your water, it can also lead to some problems long-term. The high level of chlorine in HTH can more rapidly bleach out liners and bathing suits than other chlorine products. Also, with long-term, high usage of HTH, the pool can develop calcium buildup, which would lead to calcium scaling inside of the filter and in the lines of the pool. This scaling ultimately causes damage to your filtration system, and can be avoided by using HTH in limited amounts, or by using other types of chlorines.

Why am I getting DE back in my pool?

Getting DE back into a pool is an indication of some type of problem within the filter itself. Although it could simply be a matter of using too much DE after backwashes, more often it means that a part inside the filter needs to be replaced. If you have a grid system DE filter (most inground pools have this type), it could mean that the spider gasket in the multiport needs to be replaced, that the grids inside the filter are torn, or that the manifold, which holds the grids together, has cracked. Filters with “fingers” (most aboveground systems and some older inground systems) could be torn, the diaphragm gasket may need to be replaced, or the tube sheets may have cracks in them. Check your filter carefully to make sure that all parts are in good condition, and replace necessary parts. True Blue also offers a “Clean, Soak, and Inspect” service on filters. This includes cleaning the filter elements of large debris, soaking them for 24 hours in a chemical solution, and inspecting all parts by hand.

What is the difference between Clorox and liquid shock?

Liquid shock is 12.5% sodium hypochlorite. Clorox bleach is 3% sodium hypochlorite. Although they are made of the same chemical, the percentage of chlorine in shock is much greater than Clorox bleach. To treat a 20,000-gallon pool, you would need to use two bottles of liquid shock. To achieve the same amount of chlorination with bleach, you would need to use eight bottles. Additionally, Clorox bleach contains added detergents, which could interfere with the chemical balance of your pool.

Can I use baking soda to raise the alkalinity of my pool?

Baking soda is similar to the chemical that is used to raise the alkalinity of the water, and will give you the same rise that alkalinity powder will. However, baking soda is a much larger granule, and will cloud up the water if used in great amounts. If you need to raise the alkalinity of your pool slightly, with one or two pounds of alkalinity powder, it is usually safe to use baking soda. However, if your water balance requires a significant increase, it is recommended that actual alkalinity increaser be used, as it is a finer granule and will rarely cloud the water, even if used in considerable amounts.

Can I apply chemicals through the skimmer?

Most swimming pool chemicals are not recommended to be applied directly through the skimmer. Shocks are a very strong concentration of chlorine, and if applied directly through the filter, can cause damage to the pump and filter as they pass through in such great concentration. In addition, granules that are not dissolved by the time they return to the pool can sit on the pool floor and bleach the liner. Another chemical that should never be applied through the skimmer is calcium hardness as it heats up when mixed with water and could cause damage to your filtration system and liner. Always follow the directions given to you by your sales associate when applying chemicals to your pool, to be sure that no damage is made to your valuable pool items!