Alk and Ca never seem to drop

[WhiskeyCoffee]

I've had my 75g up and running for about a year. I have about 7 softies and LPS and three LPS. All corals are growing (some more than others) and coraline algae is spreading. That being said, my calcium and alkalinity never seem to drop. I can go weeks without doing a water change or dosing anything and that CA will stay around 450 and the alkalinity will never drop below 8. Usually it's 8.4. Is this normal? I'm testing with a Salifert test kit.

 

[Dr. Reef Verified Sponsor]

Unusual. Maybe bad test kits? Have you taken a sample of water and teated against someone elses kits?

 

[Randy Holmes-Farley Verified Community Expert]

The coralline algae is likely your biggest user (soft corals use none and lps often grow slowly).

I wouldn’t worry about it. Many things can reduce growth and demand, including low pH.