difficulty discerning shade of blue in Salfert phosphate test

Ballyhoo · Jun 23, 2024

I really am not sure what to make of these test results. I've done them over over and over again and I can't tell if it's above .1 or not.

I know what I'm about to write right now is not gonna be popular and I'm sorry. i've tried Hanna and I know everyone raves about Hanna but every time I do the Hanna phos test I get a different result and I know I am going by the book, using the micro cloth to clean the test tubes, completely rinsing everything before I do it. Using all the teagent. Sometimes using 95% of the reagent but mostly using all of the reagent. I called a local coral expert and he told me Hana is not reliable for testing phosphate because the reagants could be different, he makes the point that Salifert being titration based is more reliable and it's hard to know if you're always using the same amount of reagent etc and based on what he tells me that makes sense because every time use a hanna sample I get a different result and I'm talking like back to back testing within minutes. One will show up .37 and then I'll think that's crazy and I'll rinse the sample tube thoroughly and everything and te test and then a reading .22. Another time will get a reading .44 another time I'll get a reading of .19. I'm talking about within a short span of time. i've also been very careful to make sure I extract the water sample from the aquarium with a clean tube so the sample water is reliable, aquarium sample water. I realize these statements or what I'm saying about hanna will would fall up on very unpopular ears on RF because hana is revered by most of everybody on RF as elite elite holy grail of testers. But I'm just saying my experiences and hoping somebody can point me in the direction of what my test is showing me anyways I sent out a ICP sample so hopefully they all get results back soon.

KrisReef · Jun 23, 2024

Tilt it an look at it sideways and then divide by 10,

I bought a HannaChecker to help with these difficulties.

Ballyhoo · Jun 23, 2024

KrisReef said:
Tilt it an look at it sideways and then divide by 10,

I bought a HannaChecker to help with these difficulties.

i really do not understand what you are saying : that viewing a sample of salifert titration from an angle increases the reading ten fold?
otherwise, I suppose I just have to wait to get my ICP results back.
this is the strangest thing, one lfs sells me the hanna checker telling me it's the only reliable phosphate test. But then every time I use it, it gives me a different number and someone else who specializes in corals says that the titration method is the most reliable. and the general population of reefers holds hanna as the gold standard. when you think about it though, how do you know you're always using the same amount of reagent in the packet? And how do you know the differences in the reagent volume don't have an impact on the sample reading?

Dan_P · Jun 23, 2024

Ballyhoo said:
I really am not sure what to make of these test results. I've done them over over and over again and I can't tell if it's above .1 or not.

I know what I'm about to write right now is not gonna be popular and I'm sorry. i've tried Hanna and I know everyone raves about Hanna but every time I do the Hanna phos test I get a different result and I know I am going by the book, using the micro cloth to clean the test tubes, completely rinsing everything before I do it. Using all the teagent. Sometimes using 95% of the reagent but mostly using all of the reagent. I called a local coral expert and he told me Hana is not reliable for testing phosphate because the reagants could be different, he makes the point that Salifert being titration based is more reliable and it's hard to know if you're always using the same amount of reagent etc and based on what he tells me that makes sense because every time use a hanna sample I get a different result and I'm talking like back to back testing within minutes. One will show up .37 and then I'll think that's crazy and I'll rinse the sample tube thoroughly and everything and te test and then a reading .22. Another time will get a reading .44 another time I'll get a reading of .19. I'm talking about within a short span of time. i've also been very careful to make sure I extract the water sample from the aquarium with a clean tube so the sample water is reliable, aquarium sample water. I realize these statements or what I'm saying about hanna will would fall up on very unpopular ears on RF because hana is revered by most of everybody on RF as elite elite holy grail of testers. But I'm just saying my experiences and hoping somebody can point me in the direction of what my test is showing me anyways I sent out a ICP sample so hopefully they all get results back soon.

Sounds frustrating.

Hanna is consistent test to test for the same lot of chemical. If there are test chemical differences, you could see them when comparing test results from different lots of chemical, not the same lot. So with that in mind, it seems you are running into technical difficulties with the Hanna test. Assuming that you are following the directions exactly, the water sample seems to be the culprit.

To test this idea, remove about 100 mL of aquarium water and test this sample 3 times. You should get the same results within the variation of the test for each test. If not, the issue might be how hou run the test or its the checker itself.

By the way, the ICP results won’t help you because the results are too variable, it measures total phosphorous not phosphate, and the sample can degrade during shipping.

Ballyhoo · Jun 23, 2024

OK but w all of that in mind, with my salifert I am consistently getting barely discernible blue looking straight down. Can I at least be assured that my phosphate values aren't too high then? I mean, I have been doing my best to go buy the book on the titration method. One level scoop etc. ultimately I just wanna make sure my phosphates aren't too high. also, why would the water sample be the culprit for the hanna test, but not the Salifert test? . The Sal test is always consistent showing bare tinge of light blue.

Ballyhoo · Jun 23, 2024

oh also, the ICP test package says it tests both phosphorus and phosphate. I don't know if that makes a difference.

Ballyhoo · Jun 23, 2024

also, does Hannah publish what percentage of the regent must be used in order for the test values to be reliable? I.e. use 99% of the reagent, or use of 90% reagent will give same value? They don't state that which is odd, it's very easy to have some powder left behind and not used. But they're not publishing how that affects the test results. Or maybe they are I don't see it.
what if your hands come to contact with some of the reagent as it's going into the vial? Does that affect results? I'm careful not to do that but just saying.

and I will add one last thing, if my hanna checker was correct and my values are as high as it's been saying for the last week or so I should have some algae growth and I have none. IDK

slingfox · Jun 23, 2024

For Hanna I use their phosphorous test and convert the reading to a phosphate reading. I also use a pippettor that you would see in a lab so I can consistently draw the right amount of liquid into the vial.

Dan_P · Jun 23, 2024

Ballyhoo said:
OK but w all of that in mind, with my salifert I am consistently getting barely discernible blue looking straight down. Can I at least be assured that my phosphate values aren't too high then? I mean, I have been doing my best to go buy the book on the titration method. One level scoop etc. ultimately I just wanna make sure my phosphates aren't too high. also, why would the water sample be the culprit for the hanna test, but not the Salifert test? . The Sal test is always consistent showing bare tinge of light blue.

Not sure what test you are refering to when you say titration method. No phosphate test uses a titration method.

Devisissy · Jun 23, 2024

I highly suggest nyos phosphate test. It's set up in a way to make it much easier to see the color change. It's been my go to for phosphate testing for years.

Ballyhoo · Jun 23, 2024

well, I did as suggested in a post above, I took a sample from just a quarter cup of water I was able to run two tests and the first one came .50 and the second one was .45 both very high but not the same at all. IDK but quite high though.

so I was told salifert is titration , but maybe I was told wrong.

KrisReef · Jun 24, 2024

Ballyhoo said:
i really do not understand what you are saying : that viewing a sample of salifert titration from an angle increases the reading ten fold?
otherwise, I suppose I just have to wait to get my ICP results back.
this is the strangest thing, one lfs sells me the hanna checker telling me it's the only reliable phosphate test. But then every time I use it, it gives me a different number and someone else who specializes in corals says that the titration method is the most reliable. and the general population of reefers holds hanna as the gold standard. when you think about it though, how do you know you're always using the same amount of reagent in the packet? And how do you know the differences in the reagent volume don't have an impact on the sample reading?

The distance of sample you look through when viewing straight down is 1/10th of the distance if you view the sample from the side of the sample container. For really low concentrations the instructions should tell you to read through the edge instead of straight down.

I used to have these kits but I switched to Hanna because my eyes are not very good with color density.

Randy Holmes-Farley · Jun 24, 2024

Ballyhoo said:
so I was told salifert is titration , but maybe I was told wrong.

There are no kits we use that test phosphate by titration.

A titration test means adding one solution slowly and in measured amounts to a second one until a predetermined endpoint is reached, such as a particular color change, a particular pH, or a particular ORP value.

Ballyhoo · Jun 24, 2024

Randy Holmes-Farley said:
There are no kits we use that test phosphate by titration.

A titration test means adding one solution slowly and in measured amounts to a second one until a predetermined endpoint is reached, such as a particular color change, a particular pH, or a particular ORP value.

that is exactly how i do salifert though. drop by drop until it turns red/orange - per instructions

Randy Holmes-Farley · Jun 24, 2024

Ballyhoo said:
that is exactly how i do salifert though. drop by drop until it turns red/orange - per instructions

The Salifert phosphate kit is a blue color match type of kit. You even show it above.

Pod_01 · Jun 24, 2024

Just my take on PO4 tests and this may be controversial. You don’t want it white (that is really bad), dark blue is also not the best place to be. As long as you have some blue that is above the 0.03 and below the 1 I say you are good to go.
If the blue falls between 0.03 and 0.5 I would sleep well.

Otherwise you will end up like me and have collection of PO4 test kits and they all give different results. ICP will give you another set of results.
At that point you can average them all…

smitten with ocean life · Jun 24, 2024

maybe reach out to hanna themselves? i use them because i cant stand trying to figure out those color matching things. but i dont know about holy grail hanna users. its just what i like to use. its fine to use the salifert if thats what you prefer. most people would just steer you away from the api.

Ballyhoo · Jun 24, 2024

well, I honestly have no idea where I stand on phosphates. Sal consistently gives me results that make me comfortable in terms of what it's showing as a phosphate level. But HAnna is consistently giving me high results, but never the same even when I used from the same sample collection cup for example, I took out a quarter cup of water from the aquarium and was able to do two tests from Hanna and they were different measures .5 and another .55 and I think the third was like .45 or something so that is just the most bizarre thing that hAnna is giving me weird measures. but I will say this, when I was shaking the water out once unfortunately a vial fell on hard ground. But it didn't crack or anything and it look fine but maybe there is a imperfection in one of the hanna vials that I cannot see.

NanoNana · Jun 24, 2024

Ballyhoo said:
well, I honestly have no idea where I stand on phosphates. Sal consistently gives me results that make me comfortable in terms of what it's showing as a phosphate level. But HAnna is consistently giving me high results, but never the same even when I used from the same sample collection cup for example, I took out a quarter cup of water from the aquarium and was able to do two tests from Hanna and they were different measures .5 and another .55 and I think the third was like .45 or something so that is just the most bizarre thing that hAnna is giving me weird measures. but I will say this, when I was shaking the water out once unfortunately a vial fell on hard ground. But it didn't crack or anything and it look fine but maybe there is an imperfection in one of the hanna vials that I cannot see.

These are all right at the margin of error for most home test kits. You may never get an exact match and it likely has to do with particulate in your water. Thinks like algae, pods, sand, food etc will affect the test. You’d be surprised how much your blood work results are affected by how long the blood sits before it is spun. This is something that is just static across any type of lab testing.