Check the listing for details. Brightwell Aquatics Alkalin8.3-P 4Kg Marine KH Alkalinity Buffer Powder 8.8 lbs. Condition: New. Listed at 80.99 USD. Brightwell Aquatics Alkalin8.3-P 4Kg KH Buffer Powder for all Marine Fish and Reef Aquaria.Overview: 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.Determine alkalinity in aquarium with an accurate test kit prior to supplementing. Do not add this product directly to an aquarium without first diluting in water as directed. 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 - 12 dKH (2.5 - 4.3 meq/L) will generally maintain pH within the desired range.Instructions and Guidelines: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. When used in this fashion, 1,000 g treats up to 10,000 US-gallons (37,854 L).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). [Reference: 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 sol’n at the maximum rate of 10 ml per 20 US-gallons daily until desired alkalinity is attained, then dose daily or weekly as needed (see below). 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 one- to two-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 sol’n required to maintain stable alkalinity.Guaranteed Analysis: pH-Stabilizing Components (min) 67% (670,000 ppm).Ingredients: Inorganic salts of carbonate, bicarbonate, and borate.Size: 4 Kilograms (8.8 lbs)