Aquaforest probiotic method

[spedly]

Wow...

So I did find an unused container of Pinpoint salinity calibration fluid. I used that to calibrate my refractometer and then checked the salinity of my display and fresh salt mix. Wow is it ever off. I'm measuring only about 1.021 salinity. That would explain why my calcium measurements are so off. Thanks for the tip Skimmer Juice.

[Myka]

Originally Posted by spedly

Wow...

So I did find an unused container of Pinpoint salinity calibration fluid. I used that to calibrate my refractometer and then checked the salinity of my display and fresh salt mix. Wow is it ever off. I'm measuring only about 1.021 salinity. That would explain why my calcium measurements are so off. Thanks for the tip Skimmer Juice.

That's exactly what I was getting at when I asked how you were calibrating. I'm glad you found the issue.

Also, if your RO/DI isn't perfect, using it for the Hanna Calcium Checker will throw those numbers off too. I recommend using distilled water in the Calcium Checker.

[mrhasan]

Originally Posted by Myka

That's exactly what I was getting at when I asked how you were calibrating. I'm glad you found the issue.

Also, if your RO/DI isn't perfect, using it for the Hanna Calcium Checker will throw those numbers off too. I recommend using distilled water in the Calcium Checker.

Finger prints on the vials can throw off the numbers too. I used to handle those vials using napkins

[Myka]

Originally Posted by mrhasan

Finger prints on the vials can throw off the numbers too. I used to handle those vials using napkins

Yes, so can using different sides of the vials (quartz thickness isn't always even). I always polish up the vials, and line them up in the checker the same direction every time. When I handle them to add reagents I don't touch anything except the lid and then the very bottom 1/2" of the vial (the test is taken about 1/3 of the way down the vial). They are fussy little things, but if used carefully they are very accurate. The Calcium Checker requires much more care to use properly. It's VERY easy to mess up that one. The alkalinity and phosphate/phosporus checkers are much more forgiving. I use them all the time, but the calcium one collects dust in my cabinet.

[mrhasan]

Originally Posted by Myka

Yes, so can using different sides of the vials (quartz thickness isn't always even). I always polish up the vials, and line them up in the checker the same direction every time. When I handle them to add reagents I don't touch anything except the lid and then the very bottom 1/2" of the vial (the test is taken about 1/3 of the way down the vial). They are fussy little things, but if used carefully they are very accurate. The Calcium Checker requires much more care to use properly. It's VERY easy to mess up that one. The alkalinity and phosphate/phosporus checkers are much more forgiving. I use them all the time, but the calcium one collects dust in my cabinet.

Damn those calorimeter!

[spedly]

Originally Posted by Myka

That's exactly what I was getting at when I asked how you were calibrating. I'm glad you found the issue.

Also, if your RO/DI isn't perfect, using it for the Hanna Calcium Checker will throw those numbers off too. I recommend using distilled water in the Calcium Checker.

Well I'm at a loss...

After discovering that my salinity was off I have spent the past couple of weeks getting it back up to normal levels. After a water change today, I calibrated my refractometer with the Pinpoint solution and measured the salinity in my tank at 1.025. Not the 1.026 I was hoping for but definitely within reason.

A couple of hours later I went to the grocery store to buy a jug of distilled water then used my Hanna checker to measure calcium and.....381. Hrmph. I feel like I'm back where I'm started. I'm still not seeing calcium levels others are seeing.

There are three variables that might be throwing stuff off:

- Pinpoint solution. Does this stuff expire? It's a couple of years old but was never opened until two weeks ago. Should it be shaken before use?

- Refractometer. Should I compare it at the LFS? Is it "spoiled" since I've only used RO/DI for calibration up to this point?

- Bad batch of salt mix? I'm at the end of the current bucket and will have to open a new bucket next week. Maybe wait and see what I measure from that before taking next steps?

I feel like I'm missing something obvious or maybe just have a bad batch of salt.

[Jordon]

Originally Posted by spedly

... - Refractometer. Should I compare it at the LFS? Is it "spoiled" since I've only used RO/DI for calibration up to this point?

Bingo! Although not spoiled, you can recalibrate it.

Give this a read and step away from the RO/DI!

Buy some calibration fluid stat!

[spedly]

Originally Posted by Jordon

Bingo! Although not spoiled, you can recalibrate it.

Give this a read and step away from the RO/DI!

Buy some calibration fluid stat!

Thanks Jordon. I should have been more clear. Up until two weeks ago I had only used RO/DI water for calibration. But I am using American Marine Pinpoint calibration fluid now. I'm measuring 1.025 salinity now (up from 1.021) but am still measuring lower than expected calcium levels.

[Jordon]

Originally Posted by spedly

Thanks Jordon. I should have been more clear. Up until two weeks ago I had only used RO/DI water for calibration. But I am using American Marine Pinpoint calibration fluid now. I'm measuring 1.025 salinity now (up from 1.021) but am still measuring lower than expected calcium levels.

Oh gotcha!

Have you tested both freshly mixed salt water and your tank? I'm at a loss why the Calcium would be so low. Have you tried a different test kit?

I have the Hanna Calcium checker, and always get results all over the place. I think unless the Distilled water is "lab grade" its contaminants can mess up the results.

[Myka]

I'd be trying a different test kit. I haven't seen a bucket that low in any of the three Aquaforest salts.