Can't get calcium down

Fphipps

New member
I have a 125 gallon mixed reef with a 30 gallon sump. I have mostly SPS frags, a few decent size montipora, a few LPS and some softies. I have my Alk at around 6-7 dkh, magnesium around 1400 but my calcium is off any charts on the test kits I have used. I was using a redsea test kit and it was off the chart so I purchased a salifert kit and it too reads over 500.
It seems like I can never get it down. I have tried not doing water changes weekly and lowers just a little and as soon as I do a water change it bounces right back up. I do not dose anything. I am using reef crystal as my salt mix. I am getting growth from my SPS and LPS but my calcium still stays up there.

I plan to run two part to maintain my kalk a little better as my corals grow but I would like to be able to lower and maintain my calcium around 420-450.

Is it an issue to gave calcium too high? everything looks fine and thriving, but for my piece of mind I would like it a little lower.
 

Reefer54

New member
If your stock is happy, then you should feel pretty good. Calcium above 500 is not unheard of and Kent Reef Salt at 1.025 reports a level upwards of 550. I would suggest upping your Alk to 8 - 9 range though. Mag at 1400 will also encourage your cal staying high, 1300 is a more accepted raange. See if you can up the alk and down the mag a bit, then see where your cal lies... But if all your livestock is happy and healthy and growing, maybe dont mess with at all.
 

Randy Holmes-Farley

Reef Chemist
Premium Member
You need to see how high it actually is before worrying about it. Off the charts means you need to use a second syringe of titrant until the endpoint, then add the values together. :)
 

Fphipps

New member
The issue with the calcium and Mg is that I am not adding any of it. So I can't really control it. When it starts to deplete a little bit I get excited but as soon as I do a water change the numbers go back up
 

Randy Holmes-Farley

Reef Chemist
Premium Member
Yes, but if it is 510 ppm Ca++ as many salt mixes have, its no big deal. If it is 800 ppm Ca++ for some reason (like a hydrometer issue pushing the salinity higher than you think), that requires correction. Same for magnesium.

What salt mix and salinity are you using?
 

Fphipps

New member
I know this is a bit if late response...
I use reef crystals salt and maintain 1.025. I'm using a refractometer that I calibrate before using with my RO/DI water

I'll test tonight to see exactly what my Ca levels are and if it's under 600 I shouldn't worry? Correct?
 

Portsie

New member
You should grab some 1.025 calibration fluid for the refractometer. It can make a big difference in your readings.
 

Fphipps

New member
well after a few weeks of adding some more SPS my calcium is between 470-500ppm. alk is around 7.7-8.0 so I am going to start using my kalk to maintain it until my next water change and see if I notice a pattern of how long it takes for the calcium and alk to come down before needing kalk again
 
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