Why does my reef tank have high Ca and Alk?

[Randy Holmes-Farley]

I am at my wits end! I have a 125g mixed reef with a medium to heavy bioload. Until a year or so ago, I have always dosed equal parts of 2 part solution and I had good success with my corals. Then, someone at my LFS told me that you never dose equal parts of your 2 part solution.

Ignore their advice, IMO.

That said, It is OK to deviate if needed. it just isn't needed nearly as often or to nearly the extent as folks think based on semi reliable testing for a short period of time.

As folks have noted, just stop dosing anything and let the levels drop if you want them lower.

I cannot tell what products you are dosing, but this calculator has many:

Reef Chemistry Calculator

 

[Nick Barbier]

Ignore their advice, IMO.

That said, It is OK to deviate if needed. it just isn't needed nearly as often or to nearly the extent as folks think based on semi reliable testing for a short period of time.

As folks have noted, just stop dosing anything and let the levels drop if you want them lower.

I cannot tell what products you are dosing, but this calculator has many:

Reef Chemistry Calculator

Thank you for all the advice. I have visited the reef chemistry calculator. I use Oceans Blend 2 pt solution with is on the list. I'm anxious about being able to start using the calculator once the Ca and Alk drop to within acceptable levels.

 

[chromis]

Have you bothered to check the Alk and Ca of the water you are mixing for water changes? My bet is your salinity measurement is off and you are mixing to a higher salinity than you thought (therefore all the other parameters are elevated).

 

[Nick Barbier]

Have you bothered to check the Alk and Ca of the water you are mixing for water changes? My bet is your salinity measurement is off and you are mixing to a higher salinity than you thought (therefore all the other parameters are elevated).

I have checked the salinity of a sample of water that I a mixed and it was 1.028. I have since adjusted the salinity in the tank to 1.025 and I will test the Alk,Ca, & Mg again today.

 

[Nick Barbier]

Once my parameters fall to within acceptable levels, how can I keep them there without chasing numbers? I would like to have my water parameters at: Alk: 8-9, Ca: 420-440, Mg: 1300-1350.

 

[Randy Holmes-Farley]

Once my parameters fall to within acceptable levels, how can I keep them there without chasing numbers? I would like to have my water parameters at: Alk: 8-9, Ca: 420-440, Mg: 1300-1350.

lol

Forget the term "chasing numbers". It's a throw away term to criticize how someone else maintains their tanks.

There is never anything wrong with "chasing numbers" when the actions are appropriate.

Nearly all reefers somehow have to measure alkalinity. There's no way to know how to maintain it without measuring it.

There are many ways top maintain these parameters. i describe many of them here;

The Many Methods for Supplementing Calcium and Alkalinity - REEFEDITION

There is no aspect of reef aquarium chemistry more important than calcium and alkalinity. Many of my previous articles have described various aspects of these systems in detail. In reading those articles, aquarists will note one pervasive theme: that maintaining appropriate levels of each are...

www.reefedition.com

 

[mike550]

I have checked the salinity of a sample of water that I a mixed and it was 1.028. I have since adjusted the salinity in the tank to 1.025 and I will test the Alk,Ca, & Mg again today.

@Nick Barbier what salt do you use?

 

[Nick Barbier]

lol

Forget the term "chasing numbers". It's a throw away term to criticize how someone else maintains their tanks.

There is never anything wrong with "chasing numbers" when the actions are appropriate.

Nearly all reefers somehow have to measure alkalinity. There's no way to know how to maintain it without measuring it.

There are many ways top maintain these parameters. i describe many of them here;

The Many Methods for Supplementing Calcium and Alkalinity - REEFEDITION

There is no aspect of reef aquarium chemistry more important than calcium and alkalinity. Many of my previous articles have described various aspects of these systems in detail. In reading those articles, aquarists will note one pervasive theme: that maintaining appropriate levels of each are...

www.reefedition.com

Thank you Randy for all the excellent advice. In all the years that I have been in reefing, I have never had as many issues with my tanks. Perhaps it's because I didn't know as much about reef husbandry as I do now and I might have not necessarily wanted to have the most stable tank as possible. Whatever the case, I want to have beautiful and stable tanks.

 

[Nick Barbier]

@Nick Barbier what salt do you use?

I use Red Sea salt, not Red Sea Pro.

 

[mike550]

I use Red Sea salt, not Red Sea Pro.

Okay. I was wondering if maybe you were using a high Alk salt. But to your point, the Red Sea Salt mixes close to what your target it. For what it's worth, when I make new saltwater (typ 20-25G) I always adjust Alk, Ca, and Mg to my target parameters before doing a water change. It's just another way to keep things stable in the tank.

By the way, I'm running ESV B-Ionic two part, and once I got my Alk to the level I wanted I started to dose both parts equally. What I learned along the way is that while there are targets for Alk and Ca, I'm letting the two part control the Ca level by equal dosing. Ironically, I target 8.4 dKH for Alk and the two part is holding my Ca around 450. So not complaining.

 

[Nick Barbier]

After not dosing my Ocean's Blend 2 part solution for two weeks, the Alk fell from 12.5 dkh to 7.0 dkh. I wanted the Alk to be 8.2 dkh. The Reef Chemistry Calculator indicated that I needed to dose 107 ml. After dosing for two days, I tested my 125g today. The Alk is at 8.4 dkh, that's close enough to 8.2 dkh. My question is, How do I keep the Alk at 8.4 dkh? If I keep dosing 107 ml, the Alk will sky rocket again. Do I test every few days and continue to adjust how much I am dosing.

 

[Nick Barbier]

Okay. I was wondering if maybe you were using a high Alk salt. But to your point, the Red Sea Salt mixes close to what your target it. For what it's worth, when I make new saltwater (typ 20-25G) I always adjust Alk, Ca, and Mg to my target parameters before doing a water change. It's just another way to keep things stable in the tank.

By the way, I'm running ESV B-Ionic two part, and once I got my Alk to the level I wanted I started to dose both parts equally. What I learned along the way is that while there are targets for Alk and Ca, I'm letting the two part control the Ca level by equal dosing. Ironically, I target 8.4 dKH for Alk and the two part is holding my Ca around 450. So not complaining.

Those are the exact parameters that I want to achieve.

 

[Nick Barbier]

In a side note: I haven't dosed any Calcium in two weeks as well. And yet my Ca has only dropped from 525 to 515.

 

[Albertan22]

After not dosing my Ocean's Blend 2 part solution for two weeks, the Alk fell from 12.5 dkh to 7.0 dkh. I wanted the Alk to be 8.2 dkh. The Reef Chemistry Calculator indicated that I needed to dose 107 ml. After dosing for two days, I tested my 125g today. The Alk is at 8.4 dkh, that's close enough to 8.2 dkh. My question is, How do I keep the Alk at 8.4 dkh? If I keep dosing 107 ml, the Alk will sky rocket again. Do I test every few days and continue to adjust how much I am dosing.

Ok, test your alkalinity, then don’t dose anything for 24 hours. After 24 hours (as exact as you can be), test alkalinity again, it will have dropped. This is your daily consumption. Use that drop and plug it into the calculator to see how much you have to dose to regain your target. Dose that amount, it is now your daily dose. Repeat the exercise every day for a week or two to tweak the dose and make sure you haven’t made any errors. You can then reduce testing to weekly, making adjustments as needed.

 

[Nick Barbier]

Ok, test your alkalinity, then don’t dose anything for 24 hours. After 24 hours (as exact as you can be), test alkalinity again, it will have dropped. This is your daily consumption. Use that drop and plug it into the calculator to see how much you have to dose to regain your target. Dose that amount, it is now your daily dose. Repeat the exercise every day for a week or two to tweak the dose and make sure you haven’t made any errors. You can then reduce testing to weekly, making adjustments as needed.

Will do. I appreciate the advice! I just don't understand why the Ca has barely dropped from 525 to 515, when I haven't dosed it in 2 weeks either?

 

[Albertan22]

Will do. I appreciate the advice! I just don't understand why the Ca has barely dropped from 525 to 515, when I haven't dosed it in 2 weeks either?

@Randy Holmes-Farley can explain it better, but calcium is used up at a much lower rate than alkalinity. Although we may dose equal parts of a 2 part solution that doesn’t mean we are dosing equal concentrations of that makes sense? I’d start dosing alkalinity but not calcium until calcium comes back to your target. Once that happens, go back to equal parts if that’s what you were comfortable with.

 

[Nick Barbier]

@Randy Holmes-Farley can explain it better, but calcium is used up at a much lower rate than alkalinity. Although we may dose equal parts of a 2 part solution that doesn’t mean we are dosing equal concentrations of that makes sense? I’d start dosing alkalinity but not calcium until calcium comes back to your target. Once that happens, go back to equal parts if that’s what you were comfortable with.

I will, and will post my findings in a few days. Thanks again for your advice.

 

[mike550]

@Nick Barbier sounds like you’ve made a ton of progress! I agree with @Albertan22 suggested.

To make things easier when I was doing this I measured at a specific time and then waited 72 hours and measured again. I found it was easier because there’s a bigger change and easier to measure. So just divide 3 and you have your daily consumption. Make one adjustment to get you back to 8.4 or 8.6 then do your daily dose from there.

Wait for calcium to get back to your target and then do equal parts from there.

 

[Nick Barbier]

@Nick Barbier sounds like you’ve made a ton of progress! I agree with @Albertan22 suggested.

To make things easier when I was doing this I measured at a specific time and then waited 72 hours and measured again. I found it was easier because there’s a bigger change and easier to measure. So just divide 3 and you have your daily consumption. Make one adjustment to get you back to 8.4 or 8.6 then do your daily dose from there.

Wait for calcium to get back to your target and then do equal parts from there.

Sounds great. I will post my results. Thanks for your advice.

 

[Randy Holmes-Farley]

Will do. I appreciate the advice! I just don't understand why the Ca has barely dropped from 525 to 515, when I haven't dosed it in 2 weeks either?

it drops much more slowly than alkalinity, and test results aren’t accurate enough to see fine differences.