Red Sea Coral Pro Salt - Mixing up Low Calcium?

NanoReefer26 · Sep 15, 2024

Hi!

TLDR: Why is my Red Sea coral pro salt mixing up to 335ppm calcium when the bucket says it should be at 450ppm?

Newbie here but wondering if anyone else has run into this issue or has any advice. I’m using Red Sea Coral Pro Salt. After a few months of patience, I’m wanting to add corals. So I wanted to get a base reading of what all my levels are at. I noticed my calcium was low around 300ppm which didn’t make any sense because I don’t have anything in the tank that should be using calcium. So I tested a fresh batch of salt water that I mixed up. Alk is 10.5 and Calcium is 336ppm Double checked salt level is 1.025 (checked calibration of refractometer with Rodi water) Mixed the salt for 25mins at room temperature until clear.

I’m using the Hanna Calcium checker. Followed the directions exactly, I even watched their YouTube video to make sure I wasn’t missing a step.

I’m just wondering why my Calcium is reading low when the bucket says it should be mixing up closer to 450ppm?

First thought was refractometer was not calibrated and salt level was off and I’m not ruling it out but I mix up in a in a 5 gallon bucket and put in two mounded cups of salt which always gets me to 1.025 which I think makes sense based on what I have read online. So I can’t imagine it’s off by too much.

What do you think? Bad batch of salt? Should I get a different calcium test kit? New refractometer? Am I mixing the saltwater incorrectly?

Thanks in advance.

ReneReef · Sep 15, 2024

Are you using a precision pipet with the Hanna calcium checker, to sample the 100 microliter sample water?

This one from Hanna or a similar micropipet from somewhere else.

If not, then I’m quite sure that’s the issue, giving you low readings.

NanoReefer26 · Sep 15, 2024

ReneReef said:
Are you using a precision pipet with the Hanna calcium checker, to sample the 100 microliter sample water?

This one from Hanna or a similar micropipet from somewhere else.

If not, then I’m quite sure that’s the issue, giving you low readings.

Yeah I am using the micropipet that came with the checker. So I’m not sure what the issue is.

ReneReef · Sep 16, 2024

Hmmm, oke great, but that makes it all the more strange.

I would definitely still recommend checking against a standard with a known calcium level. To rule out testing error.
Second best would be to take some of the freshly mixed water to your LFS and ask them to test.

Getting another test yourself gets you a new learning curve and additional test inaccuracy, which you do not need at the moment.

dr_vinnie_boombatz · Sep 16, 2024

What are you using for the water component - the 9mL? RODI water? I found the best results when using Hanna's deionized water (matches close to my ICP)

Deionized water (1G) - HI70436

Deionized water (1G) - HI70436 is premium quality deionized water for you research needs.

www.hannainst.com

I also found I have to shake the powder packet alot. When I cut it open I then use a tool to scrape it free so all of it gets used up. Otherwise a ton of it remains stuck in the packet, which should produce a lower reading since the sample color is not as dark.