High Calcium

[DLCalkins]

I have a Red Sea Reefer Max 625 (161 gal overall water volume). It's been up about 9 months. It has nine LPS corals but they are all small. My calcium remains relatively high (516 ppm as of this morning). It's been high since the beginning. I am not adding a calcium supplement. I've used two kits to test, Hanna and Seifert. Both are giving me the same result. Plus, I purchased calibration samples from Hanna which show the Hanna is working correctly. Nine months with elevated Ca+ but no supplementation. I started this tank with dry live rock (I think it was Marco rock but I can't remember now) and Caribsea live sand.

All levels are stable. Alkalinity at around 10, Nitrate around 8, phosphate 0.01, pH steady at 8.3. 10% water changes weekly.

My only possible explanation is that the calcium concentrations are coming from the rock and sand and will eventually start to fall. Has anyone experienced this situation? If so, how long was it before the Ca+ started to drop and required supplementation?

Thanks

 

[Peer.Boerner]

What is your salinity? Wondering maybe salinity is higher than it should be. That would drive high readings for Calcium and Alk. If you’re using a refractometer, be sure you calibrate it ideally with a solution at 1.025 or at least using RODI. If you’re buying premixed water from your LFS, be sure to check it too. You’d be surprised what you may find. Good luck.

 

[exnisstech]

In addition to verify salinty it may worth testing a fresh batch of water as see what it mixes at.

 

[DLCalkins]

What is your salinity? Wondering maybe salinity is higher than it should be. That would drive high readings for Calcium and Alk. If you’re using a refractometer, be sure you calibrate it ideally with a solution at 1.025 or at least using RODI. If you’re buying premixed water from your LFS, be sure to check it too. You’d be surprised what you may find. Good luck.

It is between 1.023 and 1.024. I mix my own from RO/DI water system so I know the salinity of the water going in. I calibrate my refractometer before taking my readings. Thanks for the reply.

 

[rtparty]

What salt?

 

[Randy Holmes-Farley]

FWIW, that calcium is fine. I recommend about 400-550 ppm for calcium. :)

 

[DLCalkins]

What salt?

Instant Ocean Reef Crystals. I've used this stuff for 20+ years.

 

[DLCalkins]

FWIW, that calcium is fine. I recommend about 400-550 ppm for calcium. :)

I agree that there's nothing wrong with the Ca+ level, per se. But I cannot understand why it is not dropping after nine months without supplementation (especially in a 160 gallon system). I know there's a complex relationship between alkalinity levels and calcium. I may need to look at that, too.

 

[rtparty]

Instant Ocean Reef Crystals. I've used this stuff for 20+ years.

There you go. That salt is known to be high in calcium and your system likely isn’t consuming enough. Test the parameters of a new batch

 

[DLCalkins]

There you go. That salt is known to be high in calcium and your system likely isn’t consuming enough. Test the parameters of a new batch

I'm just about to mix a 30 gallon batch. I'll check it.