Dosing Magnesium (Seems like it drops way more than Alk or Cal)

[TheSheff]

how long does the ph boost last on average using this 2 part? The value for me with something like kalk is that it is added slowly therefore the ph is able to stay more stable, rather than a quick boost then drop within the next hour or so.

 

[Randy Holmes-Farley]

how long does the ph boost last on average using this 2 part? The value for me with something like kalk is that it is added slowly therefore the ph is able to stay more stable, rather than a quick boost then drop within the next hour or so.

Any pH boost that goes above equilibrium with the air that is aerating the aquarium will decline over time as CO2 gets pulled in. The rate of decline depends on alk (higher alk gives a slower decline because the water is more strongly pH buffered), and one the degree fo aeration (more aeration with high CO2 air lowers it faster) but it does not depend on the additive type initially used to get to the higher pH.