Phosphate testing

[BuffaloLake]

I have a 310 gallon system running the full Triton method. I have a Trident NP on the system, backed up by Hanna checkers. I had been getting wildly different results on the readings. So I recorded the Trident results, then ran 3 Hanna tests, then took a sample for an ICP. These are my readings from that test:
Trident NP 0.22
Hanna ULR Phosphate average 0.39
Triton ICP 0.07

Nitrate was also wildly different between Hanna and Trident. But I didn’t see nitrate listed on the ICP

Kinda at a loss on what I can trust.

 

[Randy Holmes-Farley Verified Community Expert]

The Triton icp may have been around a while before testing and may have growth in it that reduced phosphate. But that is just speculation. I’d just assume the tank value is near the higher values, and unless you have a reason to want to lower it, just let it ride. :)

 

[Desert•Reefer]

I have a 310 gallon system running the full Triton method. I have a Trident NP on the system, backed up by Hanna checkers. I had been getting wildly different results on the readings. So I recorded the Trident results, then ran 3 Hanna tests, then took a sample for an ICP. These are my readings from that test:
Trident NP 0.22
Hanna ULR Phosphate average 0.39
Triton ICP 0.07

Nitrate was also wildly different between Hanna and Trident. But I didn’t see nitrate listed on the ICP

Kinda at a loss on what I can trust.

I've ran into this a few times, my Hanna & Salifert results are always higher than what I get back on ICP. I'm no chemist but i've always had a suspicion that nutrients are getting consumed by the bacteria in the water on the 2 week ride to testing.

 

[Tangdora]

How consistent were your 3 Hanna test before averaging.

 

[Desert•Reefer]

How consistent were your 3 Hanna test before averaging.

"Hanna ULR Phosphate average 0.39" he did say average lol

 

[BuffaloLake]

Thank you guys, I hadn’t thought about Bacteria continuing to consume the nutrients while in transit. I tend to feed heavy, phosphate can get out of control. I don’t have a problem with nitrates, they stay between 1-20 with chaeto in fuge. But for phosphate I’ve tried GFO in bags and in a reactor, phosban, Phos-E, and Carbon dosing. Carbon dosing is actually the most effective method I have tried for reducing phosphate. Odd thing is that NoPox doesn’t seem to drop my Nitrattes at the same time., just phosphate.

 

[Tangdora]

"Hanna ULR Phosphate average 0.39" he did say average lol

I get that. There a big difference in averaging a .22, .27 and including a rogue test of .7 to arrive at a .39 average.

 

[BuffaloLake]

How consistent were your 3 Hanna test before averaging.

Not as consistent as they should be. This morning I filled two cuvettes with tank water. Added Hanna reagent to one for C2, kept the other as C1. I then ran those same samples repeatedly. Results were 0.55, 0.64, 0.56, 0.47, 0.61.

 

[BuffaloLake]

How consistent were your 3 Hanna test before averaging.

I ran 3 tests that morning with my Hanna, 0.47, 0.31, and 0.39. That’s why I said “average”, I was not including the other tests in the average, just the Hanna

 

[BuffaloLake]

I ran 3 tests that morning with my Hanna, 0.47, 0.31, and 0.39. That’s why I said “average”, I was not including the other tests in the average, just the Hanna

 

[Tangdora]

Not as consistent as they should be. This morning I filled two cuvettes with tank water. Added Hanna reagent to one for C2, kept the other as C1. I then ran those same samples repeatedly. Results were 0.55, 0.64, 0.56, 0.47, 0.61.

Typically when I see inconsistent result I would shift focus to your actual testing procedure.

1) What are you using draw your samples. Are you using the same syringe to draw tank each time. The syringes included in the kits are junk and rely on your eye to fill it to the line. If not already using should consider getting and adjustable pipette with individual tips for each solution and tank

2) How are you storing or cleaning your vial.

3) Are you flushing with RO between test

 

[BuffaloLake]

Not as consistent as they should be. This morning I filled two cuvettes with tank water. Added Hanna reagent to one for C2, kept the other as C1. I then ran those same samples repeatedly. Results were 0.55, 0.64, 0.56, 0.47, 0.61.

Typically when I see inconsistent result I would shift focus to your actual testing procedure.

1) What are you using draw your samples. Are you using the same syringe to draw tank each time. The syringes included in the kits are junk and rely on your eye to fill it to the line. If not already using should consider getting and adjustable pipette with individual tips for each solution and tank

2) How are you storing or cleaning your vial.

3) Are you flushing with RO between test

I do clean with RO before and after. I use a single syringe to fill each. I can see that my testing technique could use some improvement. But I would think that there should be a bit more consistency in the readings when I repeatedly test the same two samples.

 

[areefer01]

They are not going to match nor should you expect them. You need to pick a source of record and be done. Save you from being exhausted.

If you want the Trident NP to be closer to Hanna's kit then you need to calibrate it using the average of 4 to 5 manual tests and throw out any anomalies. The recommended way of doing this is collect a pint of water from the same area as the NP's sample line and run your 4 to 5 manual tests using whatever checker you want. Average them out, throw out any anomalies, and then use that number for calibration. Do the same thing for phosphate. Next place your NP's sample line into the same pint of water to run the calibration. When done, move the sample line back to the normal area you use and the results should be similar outside their respected margin of error.

Hanna's nitrate checker is an odd duck. I've run into a few issues with inconsistent results and I have read similar posts here on the forum. Using the same test cuvette and cap is a must. Shaking consistently also played a role. I've experienced bad reagents while the expiration date being good (hanna replaced).

Edit: the manual tests for calibration are a new packet and water sample each test going through the full steps. Not cheating by using a blank sample to shorten the time.