Do you trust your test kits or your ICP reports more?

[taricha]

So here's the situation...
You use a test kit that is well regarded in the hobby and you are comfortable with it. You also send out for ICP results from a vendor you like.
You value consistency in your water and in your testing, and you usually like the results of both, but now they disagree.
So what do you do?
You have target values for fundamental parameters like Ca or Mg or PO4 and your kits and ICP reports are disagreeing - one telling you that you are above (or trending up) and the other below (or trending down) based on your target.

Which information do you act on?
A) your test kits, because they are immediate, you are comfortable with their day-to-day consistency and widespread use in the hobby.
B) your ICP report, because they have superior technology, a laboratory setting, precise numerical data, and experience of testing countless water samples.
C) Both - average them, and act on the cumulative information of both.
D) Neither - you ignore it and do nothing unless both ICP and hobby kits agree.

Which of these is closer to your thinking? Or is it something else entirely? @Rick Mathew @Dan_P and myself have some thought on this, but would love to hear how other hobbyists handle this.

 

[bushdoc]

I would compare this situation to my Blood Glucose testing- I have Dexcom ( continuous glucose monitor), ACCU-CHEK home blood glucose monitor and once every few months I check my blood glucose at Quest lab. Surely Quest lab is most accurate, ACCU-CHEK comes second, but I use Dexcom, because it is instantaneous and continuos.
I use ICP testing once every 4-6 months, but have to rely on hobby test kits for everyday use. I use calibration solution now and then to check accuracy of those tests.
If some results are inconsistent, I re-check and perhaps change brand.
Consistency is more important than single value, both in reefing tests and in maintaining blood glucose levels within certain limits.

 

[JGT]

Trust me more than any ICP. Only use ICP if something weird is going on in my tank that I might not be testing for.

 

[Doctorgori]

Yeah I get discrepancies with every ICP …latest showed copper was high then I re-tested with Salifert and Hanna AND the infamous ATI copper test ….
ALL 3 different…. the Salifert read 0 ….
So to answer the question: well thats a good question

Weird @bushdoc …I don’t fully trust those CGM’s…I’ve had a few 50’s pop up and used the ole finger prick and it was 10pts higher … they are good for when you feel queezy but I always verify…

 

[rtparty]

With no ICP company actually providing calibration and other references, it is becoming harder and harder to trust them.

For example, I use a Milwaukee digital and handheld refractometer that I have "calibrated" and ATI salinity NEVER matches up. ATI is almost always 2-3 points lower than both my checkers. I have a hard time trusting their salinity at this point. I know ICP doesn't test salinity but just an example.

However, as of late my Salifert magnesium kit will not read anything except 1500+. It isn't old or expired and it was spot on until one day it wasn't. No clue why or what happened.

I lean toward trusting test kits that have been around and used my tens of thousands of reefers and have a generally good reputation. But I go back and forth because I find a lot of negative reviews and faults in a lot of the test kits we use.

So, I am going to wait to hear what the "experts" think....

 

[taricha]

Surely Quest lab is most accurate, ACCU-CHEK comes second, but I use Dexcom, because it is instantaneous and continuos.
I use ICP testing once every 4-6 months, but have to rely on hobby test kits for everyday use. I use calibration solution now and then to check accuracy of those tests.

I like this analogy - I think it works for hobby water parameters in many ways.

However, as of late my Salifert magnesium kit will not read anything except 1500+. It isn't old or expired and it was spot on until one day it wasn't. No clue why or what happened.

You've done a bunch of ICP tests and a bunch of hobby titration tests. So what do you think your Mg actually is?

 

[rtparty]

I like this analogy - I think it works for hobby water parameters in many ways.



You've done a bunch of ICP tests and a bunch of hobby titration tests. So what do you think your Mg actually is?

Early on, my Salifert lined up extremely well with ATI. I think you have all those results. Couple were suspect but not many. But now? I don’t trust my Salifert at all so I wouldn’t argue that the ICP tests might be more accurate.

I’m sending off one of my last remaining ICP tests and will compare to what my Trident reads at the time of collection.

I still want to send off 3-5 test to each ICP company. Many of them will be my tank water collected at the exact same time. Then I will sneak in reference solution just to see what they say. But at $50+ per test, that’s not happening soon

 

[Dan_P]

So here's the situation...
You use a test kit that is well regarded in the hobby and you are comfortable with it. You also send out for ICP results from a vendor you like.
You value consistency in your water and in your testing, and you usually like the results of both, but now they disagree.
So what do you do?
You have target values for fundamental parameters like Ca or Mg or PO4 and your kits and ICP reports are disagreeing - one telling you that you are above (or trending up) and the other below (or trending down) based on your target.

Which information do you act on?
A) your test kits, because they are immediate, you are comfortable with their day-to-day consistency and widespread use in the hobby.
B) your ICP report, because they have superior technology, a laboratory setting, precise numerical data, and experience of testing countless water samples.
C) Both - average them, and act on the cumulative information of both.
D) Neither - you ignore it and do nothing unless both ICP and hobby kits agree.

Which of these is closer to your thinking? Or is it something else entirely? @Rick Mathew @Dan_P and myself have some thought on this, but would love to hear how other hobbyists handle this.

I believe @Lasse finds ICP a very useful tool and at one time considered ICP phosphorous results superior to that obtained with the Hanna Checker.

 

[Gumbies R Us]

I use ICP when I have something weird going on with my tank or if I want to see an overview of my entire tank's chemical levels.

 

[Dan_P]

I use ICP when I have something weird going on with my tank or if I want to see an overview of my entire tank's chemical levels.

Are you also checking up on any of your test kit results, like phosphorous?

 

[Timfish]

Every test result I take with a grain of salt. Rich Ross had an artifcial sea water standard tested with ICP and got some "curious" results back.

Skeptical Reefkeeping 12

Triton Lab ICP-OES Testing of a Certified Artificial Saltwater Standard By Rich Ross and Dr. Chris Maupin At MACNA 25 in Denver, the potential for the new

reefs.com

 

[A_Blind_Reefer]

Test kits for sure although it’s difficult sometimes. When I could see perfectly, Salifert alkalinity was consistent as can be expected from a hobby check in my experience. Shifting to Hanna eggs, using an automatic pipette to draw samples, and the seeing ai app on my phone to read the checker has been a life saver and trust experiment in itself. I find the ulr phosphate and hr nitrate to be consistent. Alk was a bit frustrating for awhile. I use an automatic pipette for this as well. You trust it until you don’t. Wether they had some reagent issues in the past, or if it degrades over time, whatever the case I had trust issues for a long time as results started drifting after a while and a new reagent result was wildly different. After reading @Lasse experiment with keeping the reagent in the fridge, I have done the same and have been problem free. I don’t know if it’s the temp, sealed environment (I’m excluding light as I kept mine in a dark cabinet before), or the reagent issue is fixed now but I’ll be keeping it the fridge in any case. Noticed I said consistent, not accurate as I have no way of validating accuracy. Even the trident is useful for me. I accept it for what it is. I don’t expect miracles. I’ve come to trust it enough to reduce my manual alkalinity testing to once a month. There are hiccups along the way but the moving average is close enough for me. Triton sounded like a great solution from a vip standpoint. Pricey, yes. It takes a lot of footwork to read the results as they are not screen reader friendly. PDFs aren’t recognizable and web charts have no organization so you don’t know what result is in what column or row. It’s impossible to decipher and requires sighted assistance. I love using Alexa to log manual tests in apex fusion as she confirms the result, tells me how long ago and what the difference was from the previous result and what the previous result was. Great for forgetful folk like myself.

 

[Timfish]

. . . After reading @Lasse experiment with keeping the reagent in the fridge, I have done the same and have been problem free. I don’t know if it’s the temp, sealed environment (I’m excluding light as I kept mine in a dark cabinet before), or the reagent issue is fixed now but I’ll be keeping it the fridge in any case. . .

This is a good point! Going around and seeing lots of different systems over the years I've seen test kits and reagents sitting on top of light fixtures and next to pumps and reagent bottles left open next to sumps. Taking care of test kits is just as important as taking care of systems.

 

[GuppyHJD]

I sent a similar question today to Reef-Labs. ICP test shows 376 calcium and Salifert is testing 440. Which do I trust?

 

[blaxsun]

Another +vote for me.