Confusing Ca and Mg test results

[PDR]

I'll admit, I have not been very consistent with testing. I just tested Alk, CA, Mg and p04 for the first time in about a year ;Facepalm

I double checked my results 2x with two different kits (the Red Sea kit was expired, but still gave similar results). Salifert and Nyos are brand new and so were the p04 reagents.

Here were my results:
Alk 7.5 (Salifert and Red Sea)
Ca 465 (Salifert and Red Sea)
Mg 1440 (Salifert and Red Sea)
Nitrate 0 (Nyos and Red Sea)
P04 0.00 (Hannah checker)

My tank is a reefer 350, all softies and anemones with a ton of coralline. It is over stocked and over fed, and I only run carbon and a fuge. The reason I'm confused is I use IO salt and do water changes every 4-6 weeks. I don't dose anything.

My understanding is that IO has approximately 400 Ca, 11 Alk, and 1350 Mg. I know the coralline is using why the alk is lower and my fuge is taking care of Nitrate and Phosphate. So why is my Ca and Mg so high?

Thanks!

 

[Randy Holmes-Farley]

High salinity would do it. Do you know what it is and how are you measuring it?

 

[PDR]

Sorry forgot to add salinity. 1.025 measured with a refractometer. Calibrated with 35ppm solution.

 

[Bayareareefer18]

Have you tested your freshly mixed salt water ?

 

[PDR]

Have you tested your freshly mixed salt water ?

I don’t have any to test today. I did test alk from it the other week and it was 10 or 10.5dkh

 

[Randy Holmes-Farley]

What do you replace evaporated water with?

 

[PDR]

What do you replace evaporated water with?

BRS 5 stage rodi.

 

[PDR]

Also I do remember having similarly strange ratios in this tank about 2 years ago when I was using HW Reefer salt. I made the switch to IO over a year ago.

 

[Bayareareefer18]

I don’t have any to test today. I did test alk from it the other week and it was 10 or 10.5dkh

Would be curious what the ca and mag are.

 

[Randy Holmes-Farley]

The ways for calcium and magnesium to rise on their own are rather unlikely to be true, and a salt mix with higher values or test kit errors, salinity errors, etc. are much more likely.

 

[PDR]

Alright guys, so I tested everything again when I got home, recalibrated my refractometer and confirmed the previous results.

For some reason I didn't think to test my anemone prop system that just got setup from the same batch of salt and only has a couple of snails and 2 small clowns.

The results for the anemone tank:
Alk 10
Ca 475
Mg 1500

I'm 99% sure I am doing the tests correctly, so it seems it was just this batch of salt. Has anyone else had numbers this high with regular IO?

My next question is how do I balance my Alk, Ca, and Mg in my 350? I want to use 2 part to keep my Alk closer to 9.5-10. After getting my Alk where I want it, do I continue to dose just Alk until Ca and Mg drop enough to start dosing? When I dosed 2 part on an older tank I remember being told to dose equal amounts no matter what. What's the correct method?

Thanks!

 

[Bayareareefer18]

Alright guys, so I tested everything again when I got home, recalibrated my refractometer and confirmed the previous results.

For some reason I didn't think to test my anemone prop system that just got setup from the same batch of salt and only has a couple of snails and 2 small clowns.

The results for the anemone tank:
Alk 10
Ca 475
Mg 1500

I'm 99% sure I am doing the tests correctly, so it seems it was just this batch of salt. Has anyone else had numbers this high with regular IO?

My next question is how do I balance my Alk, Ca, and Mg in my 350? I want to use 2 part to keep my Alk closer to 9.5-10. After getting my Alk where I want it, do I continue to dose just Alk until Ca and Mg drop enough to start dosing? When I dosed 2 part on an older tank I remember being told to dose equal amounts no matter what. What's the correct method?

Thanks!

Maybe you need to stir up your salt. Believe it was BRS that said these minerals could separate in your salt mix giving you inconsistent mixtures but don't quote me on that hours of research really starts to run together lol

 

[Randy Holmes-Farley]

They can separate. A tech guy from IO told me he put a bucket on a washing machine and was able to get it to separate like it might in shipping.

 

[Randy Holmes-Farley]

Alright guys, so I tested everything again when I got home, recalibrated my refractometer and confirmed the previous results.

For some reason I didn't think to test my anemone prop system that just got setup from the same batch of salt and only has a couple of snails and 2 small clowns.

The results for the anemone tank:
Alk 10
Ca 475
Mg 1500

I'm 99% sure I am doing the tests correctly, so it seems it was just this batch of salt. Has anyone else had numbers this high with regular IO?

My next question is how do I balance my Alk, Ca, and Mg in my 350? I want to use 2 part to keep my Alk closer to 9.5-10. After getting my Alk where I want it, do I continue to dose just Alk until Ca and Mg drop enough to start dosing? When I dosed 2 part on an older tank I remember being told to dose equal amounts no matter what. What's the correct method?

Thanks!

Those values are OK, and I wouldn't do anything unless and until the alk drops below your target.

 

[PDR]

Those values are OK, and I wouldn't do anything unless and until the alk drops below your target.

So for example, if I raise my alk to 10 and a few days later its at 9, but Ca and Mg are still elevated, should I just dose the alk part of the 2 part? My alk has never been consistent and that's what I'm trying to aim for.

 

[Randy Holmes-Farley]

So for example, if I raise my alk to 10 and a few days later its at 9, but Ca and Mg are still elevated, should I just dose the alk part of the 2 part? My alk has never been consistent and that's what I'm trying to aim for.

I don't think it will matter if you dose both parts equally to maintain alk, or just the alk part till the calcium declines a bit (but that means more calcium monitoring that you could basically ignore for a long time if you dosed both parts equally).

 

[PDR]

Alright so now I'm confused again lol. I tested alk and ca consumption over 5 days, did the math using the brs calculator and determined that I needed to dose 15ml of alk and 7ml of ca.

My starting values were 10 alk and 450 ca.

After 1 week of dosing those amounts I tested my parameters again and alk was 10.5, and ca was 480. I'm confused because according to the brs calculator I would have needed to add 230ml of calcium chloride to raise my calcium from 450 to 480, but over the week I only added 49ml of calcium.

So even assuming 0 calcium consumption over the 7 days, I would have needed to add an additional 180ml of calcium to have it increase by that much.

Any ideas?

I did the test twice to confirm both the 450 and 480 calcium values.

 

[Randy Holmes-Farley]

Alright so now I'm confused again lol. I tested alk and ca consumption over 5 days, did the math using the brs calculator and determined that I needed to dose 15ml of alk and 7ml of ca.

My starting values were 10 alk and 450 ca.

After 1 week I tested my parameters again and alk was 10.5, and ca was 480. I'm confused because according the the brs calculator I would have needed to add 230ml of calcium chloride to raise my calcium from 450 to 480, but over the week I only added 49ml of calcium.

So even assuming 0 calcium consumption over the 7 days, I would have needed to add an additional 180ml of calcium to have it increase by that much.

Any ideas?

I did the test twice to confirm both the 450 and 480 calcium values.

Each measurement has substantial uncertainty and 450 to 480 = 30 ppm is probably +/- 30 ppm. People cannot "confirm" a result by running the same test twice, although that can be helpful.

We can likely get a better measure of the calcium consumption from alkalinity changes/consumption.

 

[PDR]

Each measurement has substantial uncertainty and 450 to 480 = 30 ppm is probably +/- 30 ppm. People cannot "confirm" a result by running the same test twice, although that can be helpful.

We can likely get a better measure of the calcium consumption from alkalinity changes/consumption.

So how do you recommend I try to measure calcium accurately enough to determine dosage?

 

[Randy Holmes-Farley]

So how do you recommend I try to measure calcium accurately enough to determine dosage?

I don't. The exact calcium level is not very important to control exactly.

I recommend you dose both parts of a two part equally (assuming you use one designed for equal parts dosing) to match the alk demand, and once a week or two check calcium and see how it is doing. If it is getting too high or too low (not small changes, but ongoing trends), the alter the calcium dose a bit up or down.