The Phoshate test kit dilemma

[Ky_acc]

Hi there - I’m really struggling to find a Phosphate test kit that is accurate and reliable

I have used almost all the phosphate test kits over the years (Red Sea, tropic Marin, etc.) and I have consistently found them to be serviceable at best and useless at worst — the best I’ve used are the following but there are still issues with each:

-Salifert - easy to perform, widely used, too hard to read at low levels which makes me skeptical
-Hanna - Inconsistent results; I also do not trust the powder packs, I went to great lengths to extract all powder from the packs in a consistent manner ( dumping onto a piece of paper and using a small funnel to add) but i still do not feel confident that I’m consistently getting the same amount of reagent powder for each test
-Elos High Resolution (HR) - I thought this was the best one (easy to read and perform) however I was basically always reading near zero, even when testing water I knew to be elevated (e.g. let a piece of food sit overnight). Also this test kit has become really hard to find in the US so I can’t even re-order at this point.

Basically my issue at this point is that Im finding it hard to believe that any hobby grade test kit is able to accurately resolve at the .01-.1 range that we are interested in.

I even looked to the more expensive lab grade options Hach and Lamotte — lamotte has discontinued their low range version and now only offers a test that is in .1 increments, and Hach only offers .1 increments as well — If these more “lab grade” companies can only offer a .1 resolution why would cheap hobby grade kits be able to consistently resolve lower?

Essentially my problems come down to:
1. Is there a reliable test kit out there capable of consistently testing in the range of .01-.1
2. If not, then is the commonly stated target range of .01-.1 even relevant, are we just deluding ourselves into thinking that we can even test at this level?

Anyone have any insights? at this point I’m basically done testing phosphate and relying on ICP tests every month or two.

I’m just frustrated that phosphate is commonly stated as one of the most important indicators to test in our aquariums, but there does not seem to be a reliable test kit out there to measure…


Thanks!
John

 

[Glenner’sreef]

Interesting: I’ve never questioned (my Hanna Checker) consistency. Are you say you’ve tested your phosphates and then retested minutes later to find conflicting numbers? And the reagents I’m sure are measured for accuracy for each packet. Hanna is a reputable company. No? I will double test when I get home. Good luck. Following.

 

[SashimiTurtle]

I use a Hanna Phosphate checker HI713 and have never had any reason to question consistency or accuracy on tests. I've done 3-5 back to back tests before and they have all been within .03 of each other.

The method I've used to extract reagent with success is to thump the packet and get all the powder into the corner opposite of the dotted cut line. I then fold the packet in half diagonally so the cut lines match up. I make one single cut along the dotted line then unfold the packet. The fold will now help act as a funnel and I dump what reagent comes out into the curvette with a few flicks of my finger. I do not worry about the dust left on the inside of the packet, so long as there is nothing that will fall out with a tap on the outside of the packet.

Hanna did not design the reagent packets to be thoroughly cleaned out and you to have to extract every speck from them. As long as you get the bulk of it out the dust that remains behind will not effect your test.

 

[slingfox]

I use the Hanna phosphorus test and use their conversion chart to get a phosphate reading. You could try that approach to see if more consistent.

 

[Ky_acc]

Perhaps you all are right and I just got too focused on the powder packs and getting everything in

Appreciate the thoughts

 

[TARHEEL78]

I use a Hanna Phosphate checker HI713 and have never had any reason to question consistency or accuracy on tests. I've done 3-5 back to back tests before and they have all been within .03 of each other.

The method I've used to extract reagent with success is to thump the packet and get all the powder into the corner opposite of the dotted cut line. I then fold the packet in half diagonally so the cut lines match up. I make one single cut along the dotted line then unfold the packet. The fold will now help act as a funnel and I dump what reagent comes out into the curvette with a few flicks of my finger. I do not worry about the dust left on the inside of the packet, so long as there is nothing that will fall out with a tap on the outside of the packet.

Hanna did not design the reagent packets to be thoroughly cleaned out and you to have to extract every speck from them. As long as you get the bulk of it out the dust that remains behind will not effect your test.

0.03 is to large of an error for Phosphate in my opinion.

 

[fishyjoes]

I don't think it's possible to get a test that's absolutely accurate and precise over and over (even in actual lab settings there's variance and error).
Instead you get a test that's "good enough", test regularly and look for trends.
If phosphate is steadily increasing, you need to start doing things to reduce it.
If it's steadily decreasing, you need to do something to prevent bottoming out.
As long as the value is "about where it usually is" - then just keep doing what you're doing.

 

[Randy Holmes-Farley]

0.03 is to large of an error for Phosphate in my opinion.

Meaning the HI713, with an even larger claimed error, is not useful, or do you not believe the 0.03 ppm range he notes is acceptable for the HI713?

 

[Lasse]

Hi there - I’m really struggling to find a Phosphate test kit that is accurate and reliable

I have used almost all the phosphate test kits over the years (Red Sea, tropic Marin, etc.) and I have consistently found them to be serviceable at best and useless at worst — the best I’ve used are the following but there are still issues with each:

-Salifert - easy to perform, widely used, too hard to read at low levels which makes me skeptical
-Hanna - Inconsistent results; I also do not trust the powder packs, I went to great lengths to extract all powder from the packs in a consistent manner ( dumping onto a piece of paper and using a small funnel to add) but i still do not feel confident that I’m consistently getting the same amount of reagent powder for each test
-Elos High Resolution (HR) - I thought this was the best one (easy to read and perform) however I was basically always reading near zero, even when testing water I knew to be elevated (e.g. let a piece of food sit overnight). Also this test kit has become really hard to find in the US so I can’t even re-order at this point.

Basically my issue at this point is that Im finding it hard to believe that any hobby grade test kit is able to accurately resolve at the .01-.1 range that we are interested in.

I even looked to the more expensive lab grade options Hach and Lamotte — lamotte has discontinued their low range version and now only offers a test that is in .1 increments, and Hach only offers .1 increments as well — If these more “lab grade” companies can only offer a .1 resolution why would cheap hobby grade kits be able to consistently resolve lower?

Essentially my problems come down to:
1. Is there a reliable test kit out there capable of consistently testing in the range of .01-.1
2. If not, then is the commonly stated target range of .01-.1 even relevant, are we just deluding ourselves into thinking that we can even test at this level?

Anyone have any insights? at this point I’m basically done testing phosphate and relying on ICP tests every month or two.

I’m just frustrated that phosphate is commonly stated as one of the most important indicators to test in our aquariums, but there does not seem to be a reliable test kit out there to measure…


Thanks!
John

I´m agree with your thoughts - especially that I never ever have been able to see and judge colour changes in the hobby tests. However - I have use both Hanna Checker LR and ULR - but I normally get very high variation between readings - the first reading is normally higher than the others if you use an separate zero and repeat the actual readings.

If these more “lab grade” companies can only offer a .1 resolution why would cheap hobby grade kits be able to consistently resolve lower?

Exactly

However - as @fishyjoes state its the trend that is important not the actual value.

But I want to see if there is better opinion out there - I have purchase the new Hanna Marine Master 97115. I got it today and have done small test. One thing I notice is that if you want to do repeated readings of the same sample you can do it without a new zero as you need with the checker, The one in Marine master is ULR (you can alter between PO4 and P readings). One thing I notice - a two minute gently shaking is not needed - just a gentle shake till all substances are dissolved. 97115 have Bluetooth connection and its very easy to use

0,21 ppn PO4 is not filtered and 0.19 is filtered 0.22 µm

Sincerely Lasse

 

[TARHEEL78]

Meaning the HI713, with an even larger claimed error, is not useful, or do you not believe the 0.03 ppm range he notes is acceptable for the HI713?

The HI713 is not useful.

 

[Randy Holmes-Farley]

The HI713 is not useful.

Ok, I understand that is a reasonable opinion if trying to maintain levels in the 0.04 ppm range.

 

[jda]

I use the Phosphorous Ultra Low 736 and have water levels of po4 between 1 and 3 ppb, usually. I find it to be very accurate when using two vials, wiping them super clean and using the 3 minute timer. I can test 3 straight times and get the same number.

All of that said, I would be ok with Salifert. I am OK with "clear" since I know that there is no way that number is zero. Other than that, if there is a little color, then that is strange for my tank and would need to look into something if a retest said the same thing. I never had a darker color which would mean a lot to me - I only get these readings when I am restoring abused live rock from other tanks.

IMO, phosphate test kits are pretty easy to understand if you have the approach that po4 is a waste product and all that matters is if you have very little, some or a lot. The degrees in each variant is not all that important. Not everybody agrees with me on this, which is cool... just the way that I look at it.

 

[Ky_acc]

IMO, phosphate test kits are pretty easy to understand if you have the approach that po4 is a waste product and all that matters is if you have very little, some or a lot. The degrees in each variant is not all that important. Not everybody agrees with me on this, which is cool... just the way that I look at it.

I definitely agree with how you view things - I think there are pretty wide ranges for most parameters that don’t require the level of micromanaging we seem to believe we are capable of.


Also…

I just bought the Hanna ULR Phosphate test kit. Ugh I’m not really happy about it, but I don’t think there is another viable option out there. I feel like as soon as it arrives I’m going to remember how much I hate performing the test and will run in the the same lack of confidence in the results I had a few years ago when I was using it. I guess we will see

 

[Pod_01]

Basically my issue at this point is that Im finding it hard to believe that any hobby grade test kit is able to accurately resolve at the .01-.1 range that we are interested in.

I have to confess that I have nice collection of PO4 testers as well.

My personal opinion, as long as they show anything other than zero I am good. Zero and I get very excited.

For the forum I use Hanna, people seem to like it:

My interpretation, not zero, good… Same for NO3…