Jamaican NSW and calcium dosing issues.

[Saintnovakai]

Hi Randy. Im a new reefer in Jamaica. Huge fan. I use NSW which is the only thing cheap here on the island. My issue is that I initially bought the BRS two part Sodium Bicarbonate and Calcium chloride for dosing. I used the brs calculator to work out a starting parameter for alk and calc which I keep at 8.5dkh and 440ppm calc. So I set those. Over 3 days my alk fell and it gave me a daily dose of 0.5oz of alk daily to maintain my dkh.

Before I read your article, I heard the mantra "dose equal parts" so I matched calc at 0.5oz.

Quest:
So my issue after doing 10g water changes fortnightly is that my alk is stable at 8-8.5 but over time my calcium has fallen 20 points. How come? According to your article, I should have seen an excess of calcium as SB is half the strength of S.carbonate and im dosing equal parts. I have no visible precipitation and I suspect mag to be ok since it doesnt fall as fast and I change water every 2 weeks. I have 2 euphyllia with 9 heads total, 1 3 inch war coral, 1 palm sized rose brain I picked up off Port Royals shore and 3 tiny bumps of monti cap. Anything else is softies. I have also started carbon dosing the DIY Nopox for two weeks now. No nitrate reduction at 6ml per day.

Can you help? Thanks in advance Randy.

 

[chipmunkofdoom2]

It could be testing error, which is quite common with calcium. It also could be low magnesium. Calcium and carbonate are super-saturated in seawater, meaning over time calcium and carbonate will precipitate out of solution. Magnesium prevents this. If, however, you push your calcium and carbonate alkalinity too high without also increasing magnesium, you'll likely see precipitation until you trend back down to around natural seawater levels.

I would grab a magnesium test kit and test your magnesium. If you want to run calcium and alkalinity much higher than that of natural seawater, you'll likely need to increase your magnesium as well. Here's a good Randy Holmes-Farley article for more information:

Aquarium Chemistry: Magnesium In Reef Aquaria

 

[Randy Holmes-Farley Verified Community Expert]

I agree that 20 points is within the testing accuracy of hobby kits, but if you want to increase the calcium part, that's fine. Just make sure it doesn't rise too high.

 

[Saintnovakai]

I see. Thanks. Well I balanced out the levels yesterday to reset desired levels and I'm waiting 4 days to see what the fall off is like so I can restart dosing 2 part at calculated levels. I also upped magnesium by 50ppm too.
If I have low magnesium, shouldn't I have trouble maintaining Alk too?

I've read Randy's articles maybe more than he has since I've started reefing. lol

Good news too is that I tested nitrates a moment ago and its at about 5 from 40. I don't trust it cuz this happened like 4 days into carbon dosing and the following day it was back up. I'll test again tomorrow to compare. Phosphates were zero on the API test kit and I was thinking I was limited so I tossed quite a bit of goniopower in because I know a dose of that gives me hair algae. So I hoped that's what works.

 

[Saintnovakai]

I agree that 20 points is within the testing accuracy of hobby kits, but if you want to increase the calcium part, that's fine. Just make sure it doesn't rise too high.

Wont I get an imbalance dosing more calcium part than alk? Or is it just that ineed to replace them as depletion dictates?
Is 9dkh to 440 calcium a good balanced level?

 

[Randy Holmes-Farley Verified Community Expert]

Wont I get an imbalance dosing more calcium part than alk? Or is it just that ineed to replace them as depletion dictates?
Is 9dkh to 440 calcium a good balanced level?

No, that's not a concern as long as you are measuring calcium and dosing accordingly.

 

[Saintnovakai]

Respect!

 

[Saintnovakai]

No, that's not a concern as long as you are measuring calcium and dosing accordingly.

Hey Randy. So I corrected the dosing and things are going well. Thanks for that. I need to ask though. I started carbon dosing with the diy nopox and used the 3ml per 25 for my 75g. Thinks seemd to be stable with no nitrate drop from 40 over two weeks. I used the API test kit and checked phosphate and it never even changed colour which is 0. Since then though ive been getting dark string hairs on my sand bed which I believe is cyano and lots of stringy white hair like fuzz on my rocks. I stopped carbon dosing two weeks now but I still have the stringy hair and the cyano. If I even put 1ml of just vinegar in the tank the cyano takes off.

I really want to carbon dose and get my nitrates down but at this point im afraid to start again. Any words of wisdom?