PH of tapwater is quite low

[Barlim]

Hi, I recently started cycling my first saltwater aquarium. To start it up I bought all my water from my LFS but I want to create my own from this point on. I just checked the PH of my tapwater (after it's been through a RODI machine) and it came out as 7.4. The PH in my aquarium is around 8.2. Since this last number is quite good I want to keep it this way, but how do I do this when I start doing water changes? I read online that adding baking soda to the new water is a solution, however it was stated this would not work long term. Other than that most articles are about raising the PH of the tank which is not something I want to do, I want to raise the PH of my RODI water before it goes in the tank. If anyone has any advice or experiences to share, I'd love to hear them!

[Ratvan]

That's quite a swing. 

 

What's the PH of the water direct from LFS? How far away is it?

 

Maybe have a chat about how they make their supply and see if you can micro scale it?

[Tamberav]

did you check the pH in freshly mixed salt water? I would think the alk added would buffer it up. 

[Gourami Swami]

the salt will definitely raise the pH of the water. Testing the RO water is almost pointless, I agree with @Tamberav see what your pH is at after mixing to proper salinity.

[Garf]

Don't chase PH. The amount of make up water you are adding won't make that much of a difference. It's the PH of your saltwater mix you want to monitor. 

[Barlim]

8 hours ago, Tamberav said:

did you check the pH in freshly mixed salt water? I would think the alk added would buffer it up. 

I did not! Thank you everyone that responded, I did not know the salt mix raised the PH. I will test it again after making some soms fresh salt water 🙂