The easiest way to boost and maintain a stable pH is with the use of the right alkalinity supplements. While maintaining your alkalinity levels within range enables a more stable pH in your tank across the board, certain alkalinity supplements also provide a boost to your pH which helps us climb closer to the target of 8.3 pH we should be shooting for.

In terms of the pH boost, we already have a relative set of expectations based on the particular ingredients of the supplement. 

  • Sodium Bicarbonate should not have a measurable effect on pH.
  • Sodium Carbonate should immediately increase pH.
  • Some manufacturers blend Sodium Carbonate and Bicarbonate in a single additive.
  • Calcium Hydroxide (Kalkwasser) has a boosting effect on pH, but it is short-lived.

We examined 14 of the most popular alkalinity supplements to find out just how much of a pH boost we can expect. We also looked at the white cloud (precipitate) that forms when dosing these alkalinity supplements to draw some conclusions around the primary ingredients - Sodium Carbonate, Sodium Bicarbonate, Calcium Hydroxide, and Sodium Hydroxide. 

pH Boost and Poof  Test Results

pH Boost Experiment Results

After mixing each of the solutions above to the manufacturer's recommended concentrations, we dosed enough solution to a test tank to increase alkalinity by 1 dKH. We recorded the pH of the water before and after dosing to find out just how much of an impact each has. Bicarbonate-based solutions recorded the smallest rise in pH while Carbonate and Hydroxide based solutions recorded the largest. 

Poof Test Results Poof Test Results

We grouped the additives by what we believe to be the primary ingredient used based on the pH increases we observed and the presence of a white cloud during our "Poof Test". When dosed into saltwater, carbonate-based additives create a white cloud and Bicarbonate based additives do not. 


You can get an idea of exactly how much of a pH boost to expect based on the primary ingredients of the alkalinity solution. A quick "poof test" can help you determine exactly what ingredients are being used in terms of carbonates. Hydroxide solutions are typically not mixed with carbonate or bicarbonate and will be labeled as either "Kalkwasser" or "Lye".  

Hydroxide-based solutions are certainly the best choice for achieving a pH boost and can be up to 10x more powerful in the realm of pH boosting. The interesting fact is how concentrated the Sodium Hydroxide solution is compared to Calcium Hydroxide (Kalkwasser). While you can expect the same increase in pH with each incremental lift in dKH for both solutions, it takes far less Sodium Hydroxide (Lye) solution to make the change. 

Amount of solution required to raise alkalinity by 1 dKH:

  • Calcium Hydroxide (Kalkwasser) - 250 mL of solution
  • Sodium Hydroxide (Lye) - 5 mL of solution

**Pro Tip - Lye or Sodium Hydroxide is dangerous and must be handled carefully. It is extremely caustic and can cause some serious health problems if not handled properly. Proceed with caution and be mindful of using this chemical in your home around children and pets. 

Learn More With BRStv: 5 Ways To Raise pH In A Saltwater Aquarium

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