FOWLR - Is calcium need

[Don424]

In a FOWLR setup isn't it necessary to be maintain calcium at around 450 so coraline will grow?

 

[Brenden]

A maintained CA level will definitely help grow coralline. I do not think you need it at 450 though. Other than coralline there is no reason.

 

[Biggen]

In a FOWLR, CA levels should easily be mainted with normal water changes. I would supplement anything.

 

[tecwzrd]

Depends on the ca level of the salt mix. Some salts are known to only give you a ca reading of around 300 so doing pwc never increases the level needed. Take a reading of your well aged salt water to determine your needs. If it’s below 400 ppm then I would dose to get it higher to equal 400 ppm. Don’t dose anything in the tank without the proper test though to keep it within the proper levels. Keep in mind that a ton of other variables like sg/alk/mg/kh affect your ca level also. The following articles will help you to understand the relationship each has on each other.

What is Alkalinity?, Calcium in the Aquarium., & Solving Calcium and Alkalinity Problems.

Some just use PurpleUP to speed coralline growth also which is mostly just a ca additive.

Edit: Forgot to add that personally I use C-Balance for easy dosing since it helps keep the ca/alk/mg in balance with each other and it’s worked well for me.

 

[Biggen]

I agree with tecwzrd that some salt mixes are notoriously known for being low in Ca (Instant Ocean comes to mind). But even then its Ca value for me was ~325+ which is ok for coralline even though that is considered "low". I still had tons of coralline growth at this Ca level before I switched to Oceanic.