Calcium dangerously low

[SnazzyUrchin792]

I just finished my weekly water testing and tested calcium for the first time after getting a LPS (frogspawn). As the title states, my calcium was way too low. All other levels were fine. I use Red Sea Coral Pro salt mixed to 1.025 sg and do 15% wc’s weekly. Any ideas as to why it’s so low? Testing error maybe?
All levels:
pH: don’t have a tester
Alk (dKH): 8.8
NO3 (ppm): 5.00, not over 5, just 5
PO4 (ppm): .66
Mag (ppm): don’t have a tester
Calcium (ppm): 200
Salinity (SG): 1.025

 

[Saltyreef]

either testing error, skewed macros or salinity meter error.

RSCP mixes up to 11-12dkh @ 1.025

If your alk is running around 8.8 and your mag comes back under 1100 id say you have low salinity causing the low calcium.

 

[SnazzyUrchin792]

skewed macros

What are macros? And I’ve heard of bad batches of Hanna reagent, could that be it?

 

[SnazzyUrchin792]

I double checked current tank salinity, if all is at 8.8 does that suggest that tester is bad too?

 

[Saltyreef]

What are macros? And I’ve heard of bad batches of Hanna reagent, could that be it?

Macro elements refering to alk cal and mag.

If something like mag is low, it makes it very hard to keep alk and cal in range.

 

[Saltyreef]

I double checked current tank salinity, if all is at 8.8 does that suggest that tester is bad too?

What are you using to measure salinity?

 

[SnazzyUrchin792]

hydrometer, about to switch to Milwaukee checker, might get levels tested at my LFS tomorrow.

 

[Saltyreef]

hydrometer, about to switch to Milwaukee checker, might get levels tested at my LFS tomorrow.

if its a coralife plastic hydrometer, they usually need to be field calibrated with something like the tropic marin.

Also keep in mind most devices read @ 77degrees, even ATC needs to be warmed up.

 

[SnazzyUrchin792]

Not coralife, instant ocean brand for the hydrometer. When I said I double checked salinity, I meant current tank salinity with a water temp of 78

 

[SnazzyUrchin792]

Just tested some “new” water that has actually been in an airtight container for three days.
Alk: 9.97
Cal: 400
Salinity: 1.027

 

[vetteguy53081]

I just finished my weekly water testing and tested calcium for the first time after getting a LPS (frogspawn). As the title states, my calcium was way too low. All other levels were fine. I use Red Sea Coral Pro salt mixed to 1.025 sg and do 15% wc’s weekly. Any ideas as to why it’s so low? Testing error maybe?
All levels:
pH: don’t have a tester
Alk (dKH): 8.8
NO3 (ppm): 5.00, not over 5, just 5
PO4 (ppm): .66
Mag (ppm): don’t have a tester
Calcium (ppm): 200
Salinity (SG): 1.025

Seems odd - How are you testing it?
I too suspect false reading

 

[SnazzyUrchin792]

except salinity, I use Hanna. For salinity, I use a hydrometer which would increase the chance of a false reading, but I buy water from the LFS I work at and can confirm by refractometer it was at 1.025 upon leaving the store

 

[Randy Holmes-Farley Verified Community Expert]

Can you describe the history of the tank water? It is quite hard to get calcium that low, and without it being a rare bad batch of salt, the only way is to add large amounts of alkalinity over time, without adding any calcium.

 

[SnazzyUrchin792]

Added the one LPS on monday, other than that only have softies, change 2- 2.5 gallons of water a week, and that’s about it. Haven’t ever dosed and have only used algaecide/other chemical treatments once 5 months ago.

 

[Randy Holmes-Farley Verified Community Expert]

Added the one LPS on monday, other than that only have softies, change 2- 2.5 gallons of water a week, and that’s about it. Haven’t ever dosed and have only used algaecide/other chemical treatments once 5 months ago.

Ok, so the only chance for calcium to be that low is a very bad batch of salt (highly unlikely) or a test error.

 

[SnazzyUrchin792]

I can’t remember making any mistakes in the test, what are the chances of a bad batch of Hanna reagent?

 

[Randy Holmes-Farley Verified Community Expert]

I can’t remember making any mistakes in the test, what are the chances of a bad batch of Hanna reagent?

Assuming you used the same reagent batch to get the 400 reading on a different salt water batch, it seems unlikely, but any strange result should be replicated before looking for explanations.

 

[SnazzyUrchin792]

Testing tank calcium again now…

 

[SnazzyUrchin792]

It must be user error, because I just tested 451 in the tank after testing 200 yesterday, and I do not dose/have not done a water change

 

[Randy Holmes-Farley Verified Community Expert]

It must be user error, because I just tested 451 in the tank after testing 200 yesterday, and I do not dose/have not done a water change

All’s well that ends well.