Started dosing baking soda and ph has dropped

[JosephM]

My alkalinity had dropped to about 7 and I decided I needed to get it back up to where I wanted it, 9, and let it sit so I can figure out how much to dose daily. Well after a couple days of raising about .5 a day (I’m at 8.2 now) my ph had dropped from 8.0-7.8. I am using API and I know it’s not the best for accuracy but the color is clearly that number. I’m using Hanna to test for alk just FYI. Am I changing the alkalinity too much or why is my ph dropping?

 

[namfuak]

Were you testing PH every day and at the same time of day or was this just a one-off test of PH? How soon after dosing the sodium bicarbonate did you get this result?

I'm pretty sure NaHCO₃ will temporarily lower PH due to the addition of CO2.

 

[JosephM]

They’re all tested around midnight lol. And the last time I added any was this morning so it’s had over 12 hrs to sit in and mix up. But I didn’t test ph during the couple days I was adding. Just 8.0 a couple days ago and then 7.8 tonight

 

[taricha]

As far as alkalinity additives go, baking soda is pretty low on the pH. It can in some cases decrease the pH of the tank water a little.

 

[Randy Holmes-Farley Verified Community Expert]

I see no reason to be concerned, but if you want to raise pH, there are many ways to do it:

pH And The Reef Aquarium
http://www.reefedition.com/ph-and-the-reef-aquarium/

 

[JosephM]

I see no reason to be concerned, but if you want to raise pH, there are many ways to do it:

pH And The Reef Aquarium
http://www.reefedition.com/ph-and-the-reef-aquarium/

Okay, thank you for the consolation and I will check it out!