Coraline growth

[cplawrence]

My tank is about 5 months old now and the coraline growth on the back wall has really taken off. However, after some time, the spot will expand and then the center will eventually turn white and then flake off. As I do not have any corals outside of a couple of small hitchikers, I have not been too concerned with my calcium levels (had been pretty steady at 320). The KH has been close to 10 and the pH around 8.4 (although, my confidence in reading that test kit is not all that high). Last night I tested and the KH came in at 8 and my pH was about 8.2. The lighting is about 4 wpg PC.
That being said, is this typical for coraline growth on the glass or is it perhaps due to the low Ca? Is there some other problem going on?
Thanks,
Chris

 

[Dr.Nate]

I assure you that if you bring your calcium up to about 420, your coralline will take off (assuming your alk stays steady, of course).

 

[malkore]

There's more to it than just raising calcium. Calcium and alkalinity must be balanced with each other, and alkalinity will affect your pH. And Magnesium levels will play a role in balancing too.

That said, your calcium is a little low. Start raising it slowly, but keep tabs on your Kh and pH.

 

[jasno999]

What is a good KH test kit to use on salt water

 

[Dr.Nate]

I've used several and my favorite BY FAR is Salifert......

http://www.tsunamiaquatic.com/page/page/1980127.htm

 

[revhtree]

I have heard Rave reviews about the salifert test. I have been happy with my seachem KH test though. Very easy to do. I am about out htough and may try the salifert.

 

[Nøjo]

Is there a difference in the growth rates amongst different colours of coraline? I know that purple is the most common, yet I have a rock that is covered in bright orange coraline and would love to see some of that take off.

 

[cplawrence]

Since my alkalinity is OK, to bump up the calcium, would it then be correct that I should use calcium chloride as opposed to calcium hydroxide? If that is correct, is there any difference between the Kent products and what Greg Watson sells?
Thanks,
Chris