There are several reasons that this could be the case, but there are 2 reasons that typically explain this:

  • The most common reason is that too much chlorine has been added to the water and the test sample is “flashing out”, which means that there is more chlorine in the water than the test kit can measure. Most test kits only measure up to 5 ppm free chlorine, so if there’s more than 5 ppm chlorine present in the water, you can get a false reading of “zero ppm”.
  • The second most common reason is that the isocyanuric acid (CYA) level is very high and is “binding up the free chlorine”, which renders it useless. We typically recommend a CYA level of 30 ppm for a typical pool (the CYA level should be zero for an indoor pool), but sometimes this level can exceed 100 ppm. A CYA level this high could produce a free chlorine reading of “zero ppm” even though you know you’ve added chlorine to the pool.

No. The truth is that freshly made Sanygen Liquid Shock and Sanygen Industrial Clor really shouldn’t have much of an odor at all. When one experiences a “bleach odor,” they are typically observing odors resulting from the natural decomposition of bleach. Since Sanygen Liquid Shock and Sanygen Industrial Clor is made fresh daily, it shouldn’t exhibit a “bleach odor” at the time of purchase.

Absolutely! Sanygen Liquid Shock and Sanygen Industrial Clor never “go bad”. As bleach ages, it will undergo a natural decomposition process that results in a weaker solution that contains a lower amount of available chlorine, but even the decomposed product is safe to use in your pool. Just know that you will probably get a lower than usual chlorine reading on your test kit since the aged product now contains less available chlorine.

As stated on the label directions of both Sanygen Liquid Shock and Sanygen Industrial Clor, we recommend that the product is stored in a cool, dry, well ventilated area away from direct sunlight. The reason for this is that high temperatures and UV light will accelerate the rate at which bleach decomposes. In fact, when the temperature falls to approximately 55°F, decomposition virtually stops! Now we realize that this isn’t always feasible in the hot summer months, so try to store the product in as cool of an area as possible. And as always, please make sure this is an area where children cannot reach the product.

When many people realize that they have an algae problem in their pool, the first product they want to grab is an “algaecide”, but this is usually NOT the correct course of action. Most algaecides are preventative in nature, meaning they are not really effective at killing the algae once it has formed, but rather more effective in preventing the algae from forming in the first place. The best way to kill the algae is to “shock” the pool with Sanygen Liquid Shock or Sanygen Industrial Clor by raising the chlorine level to 20-30 ppm free chlorine and maintaining that level for several hours before neutralizing the chlorine back down to a safe level of 2-3 ppm free chlorine. Once the algae are destroyed, we recommend that you use a weekly maintenance dose of one of the Sanygen algaecides in conjunction with your Sanygen Liquid Shock or Sanygen Industrial Clor. Please contact your Authorized Sanygen Dealer for guidance on “shocking” the pool and choosing the appropriate maintenance algaecide.

No! When swimmers complain that the water is burning their eyes, it is usually because the pH of the water is out of balance. If friends or family are complaining of burning eyes, please check the pH of the water using a suitable test kit to make sure that the pH is within the recommended range of 7.4-7.6. If the pH is BELOW 7.4, use Sanygen pH Up Soda Ash to raise the pH to the appropriate level. If the pH is ABOVE 7.6, use Sanygen pH Down Non-Fuming Sulfuric Acid or Sanygen pH Down Dry Acid to lower the pH to the appropriate level.

pH is the most important element in Swimming Pool Chemistry. It affects every other chemical balance in your water.

pH is the measure of Hydrogen Ion (H+) concentration in water. It indicates the relative acidity or basicity of pool water.

pH is measured on a scale of 0 (strong acid) to 14 (strong base) with 7 being the neutral pH.

In pools a slightly alkaline pH of 7.4 to 7.6 is most desirable. This range is the most comfortable for the swimmer (eyes – skin) and provides for the optimum oxidation from your free chlorine, while maintaining water that is not corrosive or scale forming.


  • Water becomes acidic
  • Chlorine residuals dissipate rapidly
  • Eye & skin irritation occurs
  • Plaster walls are etched
  • Metal fittings, pump impeller, heat exchanger core may corrode
  • Dissolved metals may leave stains on walls
  • Rapid loss of alkalinity


  • Chlorine activity is slowed and inefficient (lack of oxidation)
  • Scale formation and discoloration of pool walls
  • Water becomes cloudy
  • Filter is overworked
  • Eye & skin irritation


To avoid pH problems: Maintain pH of 7.4 to 7.6

Please consult Dosage Chart for correct amounts of Sanygen pH Down (Sulfuric Acid) to use to lower the pH in your specific body of water.

Please consult Dosage Chart for correct amounts of Sanygen pH UP (Soda Ash) to use to raise the pH in your specific body of water.

Total Alkalinity is closely associated with pH but rather than a measure of hydrogen ion concentration it is a measure of the ability of a solution to neutralize hydrogen ions. Expressed in parts per million (ppm), total alkalinity is the result of alkaline materials including carbonates, bicarbonates and hydroxides – mostly bicarbonates. This acid neutralizing ( or buffering) capacity of water is desirable because it helps prevent wide variations or swings in pH whenever small amounts of acid or alkali are added to the pool.

Total Alkalinity is a measure of waters resistance to change in pH.

Total Alkalinity should be maintained in the range of 100 to 150 ppm.


  • pH changes rapidly when chemicals or impurities enter the water
  • pH can drop rapidly causing etching or corrosion
  • Cloudy water, decrease oxidation from disinfectant


  • pH becomes hard to adjust or will not stabilize
  • Cloudy water, decreased oxidation from disinfectant
  • Scale formations – filter problems


3lbs of Sanygen Alkalinity Plus per 10,000 gallon of water will raise Alkalinity 20 ppm.

Calcium Hardness is the measure of the dissolved calcium salts in water. Under normal conditions this should not be a problem in properly operated swimming pools. Proper ranges of Calcium Hardness vary widely but ideal level for plaster pools generally are around 250 to 350 ppm. If Calcium Hardness is low, then water may leach calcium from the pool walls, paint or equipment causing pitting of surfaces. Very high Calcium Hardness can cause scale formation and cloudy water.


5lb of Sanygen Hardness Plus in 10,000 of water will raise Calcium Hardness 50 ppm.

Hypochlorous Acid (the killing part of disinfectant) is a highly unstable molecule which dissipates rapidly in the presence of sunlight.  PROPER stabilization of chlorine with Cyanuric Acid slows the rate chlorine dissipation without compromising oxidation and disinfection activity.  The reaction of free chlorine and cyanuric acid produces a form of combined chlorine (chlorimide) which is still active enough to help disinfect and shows up as a free chlorine residual on your test kit. Proper stabilization: Requires 20 to 50 ppm cyanuric acid. Dosage: 1 to 2 lb. per 10,000 gallon of pool water. This dose is applied once annually. All other water balance issues should be addressed prior to application. If large amounts of water are turned over during backwashes or draining (fresh water), cyanuric levels may be tested: if needed use half of initial dose applied at start up.

Caution: Cyanuric acid dissolves very slowly and is best pre-dissolved in warm water before introducing into the pool water. If not dissolved if may take days for it to break down completely. Once added to the pool cyanuric acid does not dissipate. It is removed from the pool only by backwashing to waste and splash out and evaporation. Excessive amounts of cyanuric acid can interfere with the disinfection process and at levels greater than 60 to 80 ppm may cause “chlorine lock”. The chlorine is there, but is bound by the cyanuric, unable to disinfect and oxidize. Causing cloudy, green tinged water. Draining and adding fresh water is the only cure for Cyanuric Acid over treatment.

NOTE TO CHLORINE TABLET USERS: Most Stabilized Chlorine Products contain TRICHLOROISOCYANURIC ACID.   Continuous use of these tablets will lead to a gradual increase in cyanuric acid levels. Monitor Cyanuric Levels Closely.

YES the 38% sulfuric has the same pH control characteristics as the 32% muriatic acid and it will have a lesser effect on total alkalinity.

YES.  In fact it is recommended that all of your existing supply of muriatic acid be used FIRST and the old containers discarded.  Only begin using your new supply of sulfuric acid once the old supply of muriatic acid is gone.


  • Use the ENTIRE contents of the muriatic acid drum FIRST.
  • Thoroughly wash the inside of the drum with plenty of fresh, clean water.  DO NOT use bleach.
  • Discard the wash water into the pool.  It is important to rinse the drum until you are sure there is no remaining residue of muriatic acid.
  • Remove the muriatic drum label from the outside of the drum.  Miami Products will supply you with a NEW sulfuric acid label.  Please ask the driver OR call the office to request a new label.
  • Always dilute your sulfuric acid drum by adding 1 gallon of sulfuric acid to 10 gallons of water.  ALWAYS ADD THE ACID TO THE WATER.

NO, the two acids are similar in nature but remember that it is NEVER recommended that two different chemicals be mixed, regardless of what they are.  NEVER MIX CHEMICALS. 

NO, but it is STRONGLY RECOMMENDED that you do dilute your storage tank acid because it is a safer method to properly handle chemicals and it is less wear and tear on your acid feed pump.  Diluted acid also helps prevent a drastic change in pH if an equipment malfunction would occur with your feed pump or chemical controller.

NO, both of these acids can be dangerous if they are not properly handled.  As with any acid USE EXTREME CARE in handling.  Give sulfuric acid the RESPECT it deserves.  Use rubber gloves and safety goggles when handling sulfuric acid.  Do not spill it on yourself as it can cause serious burns.  Before handling sulfuric acid, be sure to familiarize yourself with all of the safety precautions that are shown on the SAFETY DATA SHEET.  Ask your driver or call our office if you need extra SDS sheets.  SDS sheets are also available on the www.sanygen.net website.

NO, it does not fume which makes it easier for you to use and is easier on the Pool Equipment in your filter room.

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