Calcium or Alk. which is more important?

[rynon]

I read, read, read, and get so many different opinions on what's more important, calcium level (high) or alk. level (high). In your opinion, which matters more? FYI, I am having major problems keeping my calcium level above 350 (yes I checked the Mg) and everything seems perfectly happy. My acros are growing like mad, possibly the reason for the low calcium levels? I have a high nutrient level (I'm sure) which probably helps growth and has only affected one acros color. I am very low tech. compared to a lot of you. My acro additions are somewhat recent (less than a year), so I'll see what happens in time. Thanks.

[tmz]

Balance between the two is important. They match up with each other to form the calcium carbonate that corals need for calcification. I shoot for 400ppm-425ppm clalcium with 3.5 -4.5meql total alkalinity. There are some very good writeups on this is the reef chemistry forum. Just find some of Randy Holmes Farley's posts.
Tom

[corndogg]

Both are very important. In fact, one needs to be proportionate to the other. But, if I had to place one before the other, I would say:


1) Alkalinity

2) Calcium

Here is a good visual that demonstrates the relationship between the two in comparison with natural seawater.


Chemplot (http://www.reefnerds.com/ChemPlot/ChemPlot.html)

[Horace]

Both are very important, however Alk has a much lower tolerance for error. This is because Ca is in great abundance in the water, while Kh is not. The safe levels of Ca are about 370 - 450, where alkalinity IMO should be run between 7- 9 dkh. If alk swings more than a couple dkh in a short period (easy to do), its possible to crash your tank. Ca on the other hand can swing a good amount before it starts causing havok.... For that reason, I test Ca about once every 3-4 weeks, yet I test alk atleast once, if not more than once a week to ensure its dead on.

[LobsterOfJustice]

Alk.

[Dog boy Dave]

What Horace said x 2

[rynon]

Wow thanks all, that's great. I really appreciate the opinions on this!!!! I always thought alk was more important but after all kinds of reading was getting confused. I used to have a alk detector in my tank, my trach. brain until my Regal tang took a liking to it, mine is high at 11 dkh right now but my corals always look extemely happy. I have not had a day ever where my corals looked bad(no polyps, poor color, have not lost one yet). Keep the opinions coming..........this is very interesting to me. BTW corndogg thanks for the link!

[rynon]

BTW I am thinking of getting a kalk. reactor, opinions? AC or heat is on pretty much all year, so evap. is about the same year round.

[trueblackpercula]

they work hand and hand .................try read some of randys articles

[tmz]

You pobably know this but fyi you can convert meql to dkh by multiplying it by 2.8. Or in reverse your 11.8 divided by 2.8=4.2-high side but ok.