API PROPER PH™ 6.5 - 240g


API® PROPER pH 6.5 automatically sets and stabilizes pH at 6.5, and also works to remove chlorine and detoxify heavy metals. It works best with Tetras, Discus, and Angelfish, and contains electrolytes to reduce fish stress. It may be used when setting up an aquarium, or when changing water


Add 1 scoop for every 10 gallons of aquarium water. Repeat dose when pH test indicates a pH change of more than 0.2.


  • What do API PROPER pH™ powders do?
    • API PROPER pH powders are pH buffers. They set the pH of aquarium water at a particular level, and also function as a dechlorinator. This means no additional dechlorinator is needed when using these products to treat water.
  • I used API PROPER pH™ and my water has gone very cloudy. Is this normal, and is the cloudiness safe for my fish?
    • The cloudiness that can be caused by API PROPER pH powders is harmless. It usually settles on its own in 24-48 hours, but the use of API ACCU-CLEAR™ water clarifier may be used to improve it. This cloudiness occurs when API PROPER pH powder is in used in water with high hardness levels, and is caused by the hardness minerals coming out of the solution. To avoid hazy water, we recommend reducing hardness levels to 100 ppm CaCO3.
  • I am trying to lower my water with API PROPER pH™ powder, but it remains high. Why is this?
    • Normally, one dose will set the pH. However, some tap water sources used in freshwater aquariums are very hard or alkaline and are strongly buffered at pH 8.0 and higher. In this case, it may require two doses of API PROPER pH™ powder to overcome the natural buffers and set pH to a desirable level. In this situation, it may be advisable to soften the water first.
  • Is API PROPER pH™ powder safe with invertebrates and plants?
    • API PROPER pH powder is safe with invertebrates, but the powders in API PROPER pH 6.5, 7.0, and 7.5 bind to some trace elements which are needed as nutrients by live plants. Therefore, we do not recommend using these API PROPER pH powders with live aquarium plants.
  • Is API PROPER pH™ powder a phosphate buffer?
    • API PROPER pH 8.2 is a bicarbonate and carbonate buffer, and contains no phosphate. API PROPER pH 6.5, 7.0, and 7.5 are phosphate buffers. Phosphate buffers are the most reliable buffers for freshwater aquariums. They are non-toxic to fish and easily “lock in” the pH for extended periods of time.
  • Do phosphate buffers stimulate algae growth?
    • No, phosphate buffers combine with essential trace elements, like iron, causing nutrient deficiencies. PROPER pH™ 6.5, 7.0, and 7.5 should not be used in aquariums where algal growth is desirable.
  • Will API PROPER pH™ powder increase carbonate hardness?
    • Carbonate hardness, also known as “alkalinity” and “KH,” is the level of bicarbonate and carbonate ions in water. The KH level is also a measurement of water’s ability to resist pH change. API PROPER pH 8.2 contains bicarbonate and carbonate buffers, and will directly increase carbonate hardness. API PROPER pH 6.5, 7.0, and 7.5 contain no carbonate hardness, but will cause a spike in KH as measured with KH test kits. These kits work by acidifying the water in the test tube, drop by drop, with a test reagent. When the water sample is adequately acidified, a color change occurs in the test tube. This is called the “end point.” The number of drops of test reagent required to acidify the sample (causing a color change) indicates the level of KH. Phosphate buffers strongly resist pH change, and will be measured just like bicarbonate and carbonate buffers. Therefore, API PROPER pH 6.5, 7.0, and 7.5, will cause an increase in KH measurements.