Alkalininity and Calcium

[jhampton_wsu]

So I thought my calcium was a bit high 500-550 (API test kit) and my alkalinity (Elos Aqua Test) was a bit low 650 so I took a water sample to my lfs and we had a conversation. His tests results also came up the same as mine A couple of things seemd obvious like checking my pwc seawater parameters I use oceanic salt mix I've checked it to be calcium around 550 (Elos Aqua Test) and 850 Alk. Anyways I was told in this conversation that my calcium may be too high because my Alkalinity is too low and with a low alkalinity that my corals aren't able to use the clacium??? He also said that magnesium some how has to be correct to keep these two balanced??? He recommended buffering my Alkalinity and seemd to think this would help lower my calcium.

 

[ccCapt]

There is a relationship between calcium, alkalinity and magnesium. I consider these must read reef chemisrty articles.
Calcium & Alkalinity by Randy Holmes-Farley
Solving Calcium and Alkalinity Problems by Randy Holmes-Farley

 

[melosu58]

Those are two good articles. I use oceanic also and experience the same calcium to alk relationship.

 

[Kurt_Nelson]

...Anyways I was told in this conversation that my calcium may be too high because my Alkalinity is too low and with a low alkalinity that my corals aren't able to use the clacium??? He also said that magnesium some how has to be correct to keep these two balanced??? He recommended buffering my Alkalinity and seemd to think this would help lower my calcium.

Sounds like you've found a good LFS. Congrats! With my understanding of ca/alk/mag, what they've told you is spot on. (I see you're in my area - I'm in South King County - so I'm guessing you must've found one of our better LFS!)

Those articles linked to are great. If you're like me, you'll have to read them a few times for it to sink in. But in a nutshell, your alk and ca need to be "balanced". Your corals can only utilize both the calcium and alklainity up to the point they're balanced. If your alk is too low for whatever your calcium is, then that extra calcium is more or less useless. And for calcium to be utilized, your mag levels should be around (roughly) 3x your calcium levels. So like alkalinity, if you mag levels are lower than that, that extra calcium isn't doing you any good either.

That second article, "Solving calcium and alkalinity..." is the BEST article out there, in my opinion.

 

[jhampton_wsu]

Thanks for everyones feedback. Now I'll try to wrap my head around those articles. At least this supports my theory that I was headed in the right direction.

 

[jhampton_wsu]

Sounds like you've found a good LFS. Congrats! With my understanding of ca/alk/mag, what they've told you is spot on. (I see you're in my area - I'm in South King County - so I'm guessing you must've found one of our better LFS!)

I'm not sure if I'm allowed to post this here with sponsors and all but I like Barrier Reef in Renton I'm sure you're familiar. Do you have any other favorites I think I've check them all out, between Renton and Lake stevens East of the Water at least once.

Thanks again for your help

 

[Kurt_Nelson]

I kind of assumed that was the shop you were talking with. Good folks there - they won't steer you wrong. I'll PM you with other info later...