wildly different results when testing calcium

[beachsidereefer]

Hi Folks,

For a year I've been using a Hanna handheld CA tester. I experienced a sps coral bleaching event and I've been troubleshooting the system.

so one of my concerns was calcium was to high. According to my hanna CA tester it was reading low around 380 ppm which seemed odd comparing to how much I've been dosing two part.

so I ordered a Salifert CA tester and I was shocked by the results. According to this test kit my CA is off the charts at over 500 PPM which is the max it can test for. Thinking I must have screwed up I tested my water again and same result!

so now i'm stuck. which test kit is right? Does anyone know of calibration process where I can test both testers with a sample of water that has a consistent calcium level? If I'm dealing with a known sample I can see which test kit is giving incorrect results.

 

[Omega0397]

I'm not sure how many ppm's of calcium that it takes to start precipitating, but I thought it was close to 500. That being said, while Hanna has good test kits, their CA test kits consistently don't have very favorable reviews. So, to answer your question, I don't know, but maybe that will spur a few thoughts on where to look next.

 

[beachsidereefer]

I'm not sure how many ppm's of calcium that it takes to start precipitating, but I thought it was close to 500. That being said, while Hanna has good test kits, their CA test kits consistently don't have very favorable reviews. So, to answer your question, I don't know, but maybe that will spur a few thoughts on where to look next.

I am seeing some calcium precipitation in the carbon and GFO reactor so these seems to support the Salifert kit is accurate.

I've used the hanna kit for about a year. I'm now wondering if it was always inaccurate or something happened at some point to where the accuracy went down hill.

either way it's a bummer cause one of my colonies is petty much fried and the others are starting to bleach out as well. dang it this hobby can be so frustrating!

 

[Omega0397]

Sorry to hear that. I know Hanna also frequently has problems with their reagents. I've had recalls on my alk reagents for them and it was frustrating to hear that all my tests for an indeterminate period of time may have been inaccurate. I'm back to using Salifert for all of my testing needs for now.

Sounds like you're done dosing calcium for a bit and need to do a small water change so the calcium levels don't drop too quickly.

 

[Steve Maxwell]

I've heard by many people on this site that the Hanna CA tester is not at all accurate...plus I just ordered a few Hanna testers from BRS yesterday and looked at the comments for the CA tester, and it was rated pretty low for this reason.

 

[beachsidereefer]

Sorry to hear that. I know Hanna also frequently has problems with their reagents. I've had recalls on my alk reagents for them and it was frustrating to hear that all my tests for an indeterminate period of time may have been inaccurate. I'm back to using Salifert for all of my testing needs for now.

Sounds like you're done dosing calcium for a bit and need to do a small water change so the calcium levels don't drop too quickly.

Yea, I've shut off both two part dosers and I'm going to test daily and monitor the drop of ALK and CA. From what I've read it's better to let the CA level drop naturally verse shocking the system with a water change.

 

[beachsidereefer]

I've heard by many people on this site that the Hanna CA tester is not at all accurate...plus I just ordered a few Hanna testers from BRS yesterday and looked at the comments for the CA tester, and it was rated pretty low for this reason.

and the hanna checker isn't cheap! guess i just ticked that money away.... I should have just stayed with the tried and true Salifert kit!

 

[Chrisfish]

I started a thread last week in reference to the Hanna calcium checker as I am very unhappy with it. I used mine for the first time last week and my reading was 556 ppm. I have a few acros doing the same as you stated yours are and am concerned. Really helpful people responsed and basically said to get the salifert CA checker, that they liked the other Hanna checkers but not CA. Good luck and I hope we both figure out what is causing the problem.

 

[Chrisfish]

and the hanna checker isn't cheap! guess i just ****** that money away.... I should have just stayed with the tried and true Salifert kit!

Your not kidding, $50 down the drain.

 

[No SPS no Care]

red sea has never let me down. im glad you found the problem.

 

[beachsidereefer]

red sea has never let me down. im glad you found the problem.

I took your advice and purchased a red sea test kit. I ran 3 test with the salifert kit and 3 with the red sea kit. I was suprised to see the delta between the two kits was 50 PPM. The average for the red sea kit was 400 PPM and Salifert 350.

I can't believe how frustrating these test kits can be. so far I've learned the Hanna CA tester is junk because I burned my corals. Since I've been using the salifert I've observed the corals have begun to recover so I believe I've fixed the high CA issue. Now using the red sea kit it appears my CA is low, but if I raise CA then I risk burning my corals all over again because how can I be sure the red sea kit is accurate?

there's some days I just hate this hobby....

 

[jd371]

I had Red Sea, when it was nearly finished I decided to switch to the Hanna. The first test with the Hanna was way over what I would get with the Red Sea, so it got me thinking which one of these is correct. I bought a Salifert test and decided to run the test with all three. Salifert and Red Sea where always within range of each other, but the Hanna was consistently reading higher than the other two. I'm using Salifert now. Paid $50 for the Hanna and only ran three tests with it before scrapping it, not to mention that it's a PITA to use compared to the ALK or PO4, what a waste.

 

[beachsidereefer]

I had Red Sea, when it was nearly finished I decided to switch to the Hanna. The first test with the Hanna was way over what I would get with the Red Sea, so it got me thinking which one of these is correct. I bought a Salifert test and decided to run the test with all three. Salifert and Red Sea where always within range of each other, but the Hanna was consistently reading higher than the other two. I'm using Salifert now. Paid $50 for the Hanna and only ran three tests with it before scrapping it, not to mention that it's a PITA to use compared to the ALK or PO4, what a waste.

when you say the salifert and red sea are within range what type of deviation did you see? I'm seeing about 50 PPM between the two.

 

[jd371]

when you say the salifert and red sea are within range what type of deviation did you see? I'm seeing about 50 PPM between the two.

I'm sorry this is going back 2 months, but I remember one test was at 370 and the other was at 400, I don't recall which was which, but it was a 30PPM difference.

 

[beachsidereefer]

I'm sorry this is going back 2 months, but I remember one test was at 370 and the other was at 400, I don't recall which was which, but it was a 30PPM difference.

with the red sea kit do you measure 5 ML of water from the bottom, tip of nipple of the plunger or do you measure 5 ml from the first black ring just above the nipple?