Fritz RPM Calcium Buffer System Pt 2 Calcium

  • Highly Concentrated Liquid Calcium

  • Add in Equal Parts with Fritz RPM Pt 2 Calcium

  • Individual Alkalinity, Calcium, and Magnesium Formulas

  • Great for Dosing Systems

  • Same High Quality Ingredients as RPM Marine Salt Mix

  • No Uneccessary Trace Elements

About Fritz RPM Calcium Buffer System Pt 2 Calcium

It is impossible to maintain a healthy, vibrant marine aquarium without also maintaining the proper levels of calcium and alkalinity. Fritz RPM Calcium Buffer System allows aquarists to maintain these two critical components in their proper ionic balance. Unlike other similar products, Fritz Calcium Buffer System does not contain unmeasured and unnecessary ions and metals, which unchecked can lead to toxicity in the aquarium. Part 2 is formulated to provide the highest purity calcium, and when used in conjunction with Part 1, along with regular water changes with a high quality salt, will provide the correct ionic balance necessary for healthy and beautiful coral, fish and invertebrates.

Guaranteed Analysis: Calcium (min) 55,000 ppm

Ingredients: Deionized water, calcium chloride

Directions & Dosage

Adjustment Dosage: Shake well before using. Begin by measuring the calcium concentration of the aquarium water and determine how much you wish to increase it. Each mL of Pt 2 will increase the calcium in 1 US gallon (3.78 L) of water by 15 ppm. One teaspoon (5 mL) will raise 10 US gallons by 7 ppm. Do not exceed 10 ml per 10 gallons daily.

Routine Dosing: Shake well before using. Before beginning routine dosing, adjust the alkalinity to within the range of 8-11 dKH (2.8-3.9 meq/L). Once calcium has been adjusted to the desired level, recommended starting dose is 5 mL (1 tsp) each of Pt 1 and Pt 2 per 20 gallons of aquarium water per day. Maintain calcium levels between 400-450 ppm by testing daily and adjusting dose accordingly. Depending on the degree of calcification occurring in the aquarium, dose may have to be significantly increased over recommended starting dose to compensate for daily consumption.

  • For best results, add RPM Elements to a sump or high flow area of the the tank
  • No equipment restrictions necessary
  • No contraindications: can be used with all of our other products and meds
  • Safe for invertebrates
  • Easy measuring: the 4 oz, 8 oz and 16 oz bottle caps are approximately 5 mL volume; 32 oz bottle caps are approximately 10 mL volume
  • Some cloudiness is normal. Allow cloudiness to dissipate completely in between adding Pt 1 and Pt 2
  • Overdosed? Observe livestock for distress, perform small water changes if needed
  • Test for calcium with reliable calcium test kits

NOTE: If magnesium levels are too low, the addition of calcium and alkalinity supplements will simply result in the chemical precipitation of calcium carbonate. Adjust the magnesium concentration first with Fritz RPM Liquid Magnesium before adjusting calcium and alkalinity.


Size Treats Item Number
16 oz / 473 mL See Directions 80305
32 oz / 946 mL See Directions 80306
1 gal / 3.78 L See Directions 80308
5 gal / 19 L See Directions 80309



See below for frequently asked questions regarding Fritz RPM Calcium Buffer System Pt 2 Calcium.

  • I’ve noticed my RPM calcium is cloudy and I’m worried I’m not dosing enough. Is it still good?

    Yes, the product is still good and does not require any change in the dose on the label. RPM Elements Calcium may become cloudy or develop a small amount of white precipitate over time during storage. We’ve tested samples of cloudy product and determined the concentration still meets the guaranteed analysis, regardless of cloudiness or presence of the carbonate precipitation. The product does not need to be shaken up before dosing or being used in a doser.

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