Alkalinity Dropping, Calcium doesnt

[merfury1989]

I am using Red Sea Foundation A and B for dosing.
What I noticed is the following:

Day 1:
Alk = 9dkh
Cal = 487ppm

Day 4:
Alk = 8.8dkh
Cal = 498ppm

So, I can see my tank is consuming 0.5dkh Alkalinity per day, but whats happening with Calcium here?

I know if Alk drops, Cal tend to rise, and vise versa. But if Alk is getting consumed, isn't the Cal supposed to be consumed at the same ratio?

By the way my Mag is at 1,480ppm.

 

[gbroadbridge]

I am using Red Sea Foundation A and B for dosing.
What I noticed is the following:

Day 1:
Alk = 9dkh
Cal = 487ppm

Day 4:
Alk = 8.8dkh
Cal = 498ppm

So, I can see my tank is consuming 0.5dkh Alkalinity per day, but whats happening with Calcium here?

I know if Alk drops, Cal tend to rise, and vise versa. But if Alk is getting consumed, isn't the Cal supposed to be consumed at the same ratio?

By the way my Mag is at 1,480ppm.

For each 1 dkh of Alk consumed, Calcium drops by around 7-8ppm.

7-8 ppm Ca drop is in the noise for all Hobby grade test kits.

Your 0.2 dkh drop (which is also not measurable to that accuracy) is about a 2ppm Calcium drop - unmeasurable.

The variation you are seeing is simply due to test error.

 

[merfury1989]

So in this scenario should I just top up Alk back to 9dkh, and leave Cal?

 

[gbroadbridge]

So in this scenario should I just top up Alk back to 9dkh, and leave Cal?

How old is your tank and what size?.

I'm no expert on Red Sea supplement dosing as I use a different system, however someone else will be sure to pop up

 

[Randy Holmes-Farley]

For whatever strange reason, the Red Sea foundation products are not designed for 1:1 dosing. One should expect to dose more of the alk product.

if calcium is 500+ ppm, I’d skip it entirely.

 

[DeputyDog95]

For whatever strange reason, the Red Sea foundation products are not designed for 1:1 dosing. One should expect to dose more of the alk product.

if calcium is 500+ ppm, I’d skip it entirely.

It's 3 parts Alk to 1 part Ca.

Yeah, it's weird but it's how they do it...


OP

Dose Alk based on your test results and then simply dose 1/3 of that for Ca. Your Ca will be remain in an acceptable range.

If it's a newish tank with low a bioload, it make take a while to balance out the demand. I would focus on testing the Alk on a regular basis and simply keep dosing the Ca based on the instructions. It'll work itself out.
As others said, hobby Ca test kits have a widish margin of error and I wouldn't test Ca more than once a week to get a handle on the consumption trend. And even then, I think you'll find that given a little time, following the recipe works pretty well.

 

[merfury1989]

Thanks for the insight guys.

Here are few details:
My tank is a 90L tank (23.7G).

Tank is around 8mnt old.

Tank Inhabitants include:
1) Ocellaris Clowinfish (x2)
2) Blue Damsel
3) Royal Dottyback
4) Flame Bubble Tip Anemone
5) Torch Coral
6) Palythoa
7) GSP
8) Elegance Coral

For tests I use:
Alkalinity - Red Sea
Calcium - Hanah
Mag - Red Sea

 

[gbroadbridge]

Thanks for the insight guys.

Here are few details:
My tank is a 90L tank (23.7G).

Tank is around 8mnt old.

Tank Inhabitants include:
1) Ocellaris Clowinfish (x2)
2) Blue Damsel
3) Royal Dottyback
4) Flame Bubble Tip Anemone
5) Torch Coral
6) Palythoa
7) GSP
8) Elegance Coral

For tests I use:
Alkalinity - Red Sea
Calcium - Hanah
Mag - Red Sea

Sounds good for that size tank.

On the test kits, just keep in mind the Hanna Ca test is very fussy. You need to measure very accurately and consistently to get reliable results.

It's a very good test if you have the patience to use it properly. Keep in mind the accuracy is +- 6% so a reading of 450ppm means it could be anything from 420-480. It has a similar accuracy to other brands the important thing is to simply keep the number in the right range.

I find the RS Alk test does not last that long once opened, especially if you ignore the instructions and put reagent back from the syringe into the bottle. I prefer Salifert

 

[DeputyDog95]

Thanks for the insight guys.

Here are few details:
My tank is a 90L tank (23.7G).

Tank is around 8mnt old.

Tank Inhabitants include:
1) Ocellaris Clowinfish (x2)
2) Blue Damsel
3) Royal Dottyback
4) Flame Bubble Tip Anemone
5) Torch Coral
6) Palythoa
7) GSP
8) Elegance Coral

For tests I use:
Alkalinity - Red Sea
Calcium - Hanah
Mag - Red Sea

Your tank is pretty new and you don't really have much in the way of heavy Ca consumers...

Keep on course, it'll work itself out.

I prefer the Hanna Alk and Ca kits. Provided you follow the instructions precisely, the Hanna Ca is reliable and repeatable. I love both of those kits as they're easy to use and no color interpretation. The Ca has a lot of steps, relatively speaking, but they include a .10ml auto pipette now which makes it super easy to use. Apparently back in the day they didn't, and the results were all over the place as your water sample for the test is .10ml. Which is pretty easy to mess up with such a small sample.

For Mg, I use the Salifert. Also pretty easy, just a few steps and the color change is dramatic.

 

[merfury1989]

For each 1 dkh of Alk consumed, Calcium drops by around 7-8ppm.

7-8 ppm Ca drop is in the noise for all Hobby grade test kits.

Your 0.2 dkh drop (which is also not measurable to that accuracy) is about a 2ppm Calcium drop - unmeasurable.

The variation you are seeing is simply due to test error.

This makes sense, and I can see the deviations are very small for it to be detectable. Considering this, should I just dose Alk by 2ml (Red Sea Foundation B - 0.5dkh per ml), and Calcium by 0.66ml (Red Sea Foundation A - 15ppm per ml) every day?

 

[arcangelreef]

This makes sense, and I can see the deviations are very small for it to be detectable. Considering this, should I just dose Alk by 2ml (Red Sea Foundation B - 0.5dkh per ml), and Calcium by 0.66ml (Red Sea Foundation A - 15ppm per ml) every day?

Honestly, at this point you really don't need to dose anything.
You have unmeasurable consumption right now.
I would just keep an eye on it, test once or twice a week for 2 or 3 weeks and get a better idea of whats going on before you start throwing stuff in the tank.