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 above. In this case it may require two doses of PROPER pH to overcome the natural buffers and set the pH to a desirable level. In this situation, it might be advisable to soften the water first.
My Tap Water Ph Is 7 But My Aquarium Ph Is 6 With Water Chan..
Most of us in the fish keeping hobby are at least vaguely familiar with pH in the aquarium. There is, however, another water parameter that has a very close relationship with pH, but is much less understood. The water KH, or carbonate hardness, is the water’s ability to absorb and neutralize acid. KH is also referred to as alkalinity, not to be confused with alkaline on the pH scale. It is for this reason that aquarists use the term basic when referring to the pH scale instead of alkaline, and use the term alkalinity in reference to KH. Having a low KH will cause more fluctuations in the pH of the water, which can cause what is referred to as pH shock. This can happen as a result of CO2 production from fish, causing large pH downshifts, which lessen the water’s buffering ability (KH). Saltwater aquariums have a naturally high KH, but safe KH levels for freshwater should be 4.5 dKH or higher. PH shock will occur if the KH drops below 2 or 3 dKH. If water KH is low in the aquarium, regular water changes will help increase these levels. A good natural KH buffer is crushed coral substrate, but most KH buffers are based on baking soda (sodium bicarbonate, NaHCO3). Having higher KH is definitely healthier for fish. The pH will have more stability and be much less likely to crash.
The Best Ways to Raise the PH in a Saltwater Aquarium - Pets
If you want a comprehensive water & pH test kit for freshwater aquariums (can also be used for saltwater but requires a different color chart), then look no further than the API Freshwater Master Test Kit, that contains over 800 tests that measure the most important aquarium levels (freshwater pH, ammonia, nitrite, high range pH and nitrate) in 6 different ways.
Aquarium Water Testing: Aquarium Pharmaceuticals pH Test Kits