Brightwell Aquatics Alkalin8.3-P Dry Ph/Alk Buffer 500GM

CODE: BA01099


In Stock


Powdered alkalinity (KH) buffer supplement for all marine aquariums



Helps increase pH stability in an aquarium by raising the alkalinity



Provides a source of carbonates for reef-building organisms



Increase aquarium pH stability and replenish carbonates important to reef-building organisms. Alkalin8.3-P alkalinity (KH) buffer powder is a highly effective powdered blend that increases and maintains alkalinity to a desirable level. Formulated by a marine scientist, Alkalin8.3-P provides a source of carbonates important for developing skeletal material in reef-building organisms. Continued addition of Alkalin8.3 also raises pH and maintains it at 8.3. For marine and reef aquariums. 500 grams treats up to 5,000 gallons.

Extremely effective powdered blend alkalinity increasing buffer is formulated for the hobbyist maintaining particularly large or multiple aquariums. Continued use will raise the pH to 8.3, at which point only alkalinity will increase. Also provides a valuable source or carbonates for reef formation and construction by your invertebrates. Formulated by marine scientists.


  • Highly-effective alkalinity-increasing (”buffer”) powdered blend.
  • Helps increase pH stability in an aquarium by raising the alkalinity; continued addition raises pH until 8.3 is reached, at which point the pH remains unchanged and the alkalinity alone increases.
  • Provides a source of carbonates, which make up the majority by weight of aragonite, the mineral secreted by reef-building organisms as skeletal material.
  • Formulated by a marine scientist.


  • Basic:
  • Dissolve 2 grams (½ teaspoon) of product per 20 US-gallons of aquarium water in 8-fl. oz. of fresh water; add every other day or as needed to maintain the alkalinity within a range of 7 - 12 dKH.
  • Advanced:
  • Create a stock solution by dissolving 20 grams (5 teaspoons) of Alkalin8.3-P in 8-fl. oz. of fresh water (preferably purified); each ml of the solution will increase the alkalinity in 1 US-gallon (3.785 L) of water by 0.36 dKH (0.13 meq/L).
  • Note: Each g of Alkalin8.3-P will increase the alkalinity in 1 US-gallon (3.785 L) of water by 6.8 dKH (2.5 meq/L).
  • If initial alkalinity in the aquarium is below 7 dKH (2.5 meq/L), add the stock solution at the maximum rate of 10 ml per 20 US-gallons daily until desired alkalinity is attained, then dose daily or weekly as needed.
  • Maintain the alkalinity within a range of +/-1 dKH.
  • Once the desired alkalinity has been acquired, measure the alkalinity at the same time each day over a 1-2 week period to determine required dosing rate.
  • To determine the daily dosing rate (preferable to weekly dosing): estimate the volume of water in the entire aquarium system; divide the daily decrease in alkalinity by 0.36 when measuring dKH or by 0.13 when measuring meq/L; multiply this number by the volume of water (gallons) in the system to get the daily ml of stock solution required to maintain stable alkalinity.
  • Note:
  • If pH does not reach desired level when using this product as directed, such as when gas exchange in the aquarium is insufficient, addition of a pH-increasing product (i.e. Brightwell Aquatics pH+) may be required.
  • Follow manufacturer’s directions for using such a product regardless of which one is used.
  • Caution:
  • Contains carbonate and bicarbonate salts; harmful if swallowed. If swallowed: give water, get medical attention.
  • May cause eye or skin irritation. If in eyes, flush with water for 15 minutes, get medical attention. If on skin, wash thoroughly with water.
  • Keep out of reach of children.
  • Not for human consumption.

Technical Background

  • Alkalinity, also referred to as carbonate hardness or buffering capacity, is essentially a means of quantifying the stability of pH in a solution, such as aquarium water. In an aquarium, weak acids formed by oxygen respiration and the decomposition of organic material gradually deplete alkalinity. If left unchecked, the alkalinity drops below a critical level and pH begins to fluctuate more wildly than is normally suggested (a daily pH shift of +/-0.2 is normal in marine aquaria), causing stress to livestock. Alkalinity is also depleted by reef-building organisms during the production of aragonite (~60% carbonates by weight), and is therefore very important for their rapid growth. Maintaining the alkalinity in marine aquaria between 7 to 12 dKH (2.5 - 4.3 meq/L) will generally maintain pH within the desired range.

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