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View Full Version : Low alk/kh cause low ph?


PaulieReef
08/25/2013, 02:50 PM
After reading multiple articles, I am undetermined. Does Alk/kh effect your pH? I have read articles that say yes, and articles that say no. Some lead you to believe there are other reasons your pH is the way it is, and others directly blame it on low alk/kh. So I am asking people with direct experience, live in this forum post, what are your thoughts.

Does low alk/kh effect pH? Reason I am asking is my pH is currently sitting at 7.8 and my kh is at a low 7.5. So I was planning on raising my kh (since it is on the lower side) to see if that helped my pH. Was planning on doing this with some titration of baking soda.

CanuckReefer
08/25/2013, 03:04 PM
I know that adding baking soda for alkalinity will drop the ph slightly. If you bake the baking soda in the oven before adding it, the ph will rise slightly instead.

downbeach
08/25/2013, 03:12 PM
Although a little low, they're both within acceptable limits. Low pH is most likely due to elevated levels of CO2 in your household atmosphere, with windows all closed up. Try opening some windows.

bertoni
08/25/2013, 03:19 PM
The alkalinity and carbon dioxide content of the water determines the pH. You need to know both. For the recommended range, 7-11 dKH, the change in pH due to alkalinity tends to be small. This article has a graph:

http://reefkeeping.com/issues/2004-09/rhf/index.htm

The numbers you quotes are okay as is, although I'd try to keep the pH from falling further.