My Frustration With Phosphate Testing

[@JFTB-i8y]

why wouldnt you just pick 1 kit and just look at your corals and shoot for whatever number that kit says it is when your corals have good color?

[@ReefBum]

That is what I am doing.

[@telegraham]

Hanna's accuracy @ 25°C (77°F) is ±0.02 ppm ±5% of reading. Assuming you have the Milwaukee MI412. It has an accuracy of +/- 0.07 mg/L @ 1.00 mg/L. That makes me think that 0.02 and 0.04 are the same. Thoughts?

[@ReefBum]

I don't know Jim. Sometimes I even get very different results when I do back to back tests.

[@Malick_ibn_dinar]

What’s the difference between 0.02 & 0.04 ? They are both hobby grade test kit and there is no way you gonna have a stable result since they have different calibration

[@coralxplorer]

Keith, have you considered buying the Hanna Phosphorous Ultra Low Range? Its readings have almost exactly matched ICP values when I’ve cross checked them (both sampled same day).

[@ReefBum]

I may have that one someplace.

[@JTReef]

I personally use the Hanna ULR. I’ve found it to be pretty precise. Meaning I can be at 0 ppm and dose to .10ppm with a homemade solution and it gives accurate results. I use Loudwolf lab grade sodium phosphate coupled with the James planted reef calculator to make my solution. 6 grams dissolved in 500ml of Ro/di will yield a result of .05ppm per 5ml dosed. This is based off a tank Volume of 212 gallons. Pretty cool calculator. The calculator says Potassium Phosphate and there’s is a conversion to get the grams exact when using sodium phosphate. It’s 77% of the amount. I don’t find it makes a huge difference. Especially when using hobby grade test kits.

[@BryznsReef]

Any input on how accurate ICPs are for phosphates?

[@rolbar9406]

you need to try the Hanna Phosphorus test kit

[@coralxplorer]

I would argue the ULR Phosphate and ULR Phosphorous, are not equally sensitive. The ULR Phosphorous tests in parts per billion, with a smaller degree or error. And it has consistently matched ICP samples taken the same day I test with it.

[@philbert3866]

What's your process to adjust up or down if needed?

[@jules2545]

For me, I thought I had got the measure of Phosphate in my reef tank. Then I carried out an ICP test and find the test kits only measure one form of phosphate. I have stopped chasing test kit numbers and see what the corals seem to be happy with. You mention the values 0.02 & 0.04 from the test kits, what are the errors associated with these particular test kits? The chances are the difference between the two tests is lost in the errors that come from the tests?

[@ReefBum]

Yes, standard errors for kits certainly come into play.

[@floweringreefs206]

What I do is I take 3 readings with the Hanna checkers and I will take the average of the 3 results however I don’t test too frequently I test maybe once a week or once every two weeks… hope it helps

[@m4a1JAY]

You’re only measuring the free phosphate in the water column. There’s a lot of phosphate somewhere else like in the aragonite (sand and rocks) I’ve always had zero phosphate reading but I still get algae and good coral growth.

[@84DavidM777]

Makes me wonder. If you test twice on a row do you get same results on the test kits? Then you can just factor on offset each time you test. This would be nice to know since you can verify with ICP Keith. Good vid

[@Mark-hb2zy]

My phosphates are always 0 on salifert. Now I just go by algae. As long as there's a tiny bit of algae somewhere in the tank I know I've got some.

[@Sammy31Dee]

Yea you gotta use a Nyos Test for this....at least in my xp....the nyos was spot on vs a triton ICP....

[@Sammy31Dee]

And you know NYOs isn't a joker company like these other folks are....jumping into reefing sales bc they have products that can cross industries....nyos has developed all theor own stuff... I trust them for my No3 and Po4 bc as I said above they were spot on vs triton-lab icp

[@Sammy31Dee]

I've actually been considering dumping all the controllers, testers etc and trying the spintouch duo water tester... hell I use the jebao dosers and neptune dosers and the only actually benefit is the app....and that's pointless if you buy a proper power bar with individual switches

[@attackcustombaits8446]

Easy's answer is pick one stick with that. Long as it does not read 0, you are good.

[@johngraves2185]

I’m not a big fan of ratios, but rather ranges. I also think most people keep PO4 too low in aquaria. I think 0.1 - 0.2 is a good range without causing any major issues and if N is 1ppm or slightly above, you have more than enough nitrogen feeding the system. Algae issues are a herbivore issue, not nutrients. I’ve been using the Hanna ULR phosphorus for years and it’s served me well. As you mentioned, knowing how to observe healthy corals is far more important in my book, and the numbers just give me a range that they thrive in. I think too many people focus on what the natural reef’s numbers are and try to replicate that and that’s where things go wrong., Our tanks are so far removed and different than natural reefs, so trying to match those numbers just cause more problems, mostly coral mortality. Cheers!

[@ellisbarton2261]

Fauna marins phosphate kit is accurate to their ICP i have found. worth a try for sure

[@laurens6267]

The red sea po4 test kit for me has always been consistant and the same as my icps. To me it seems precise within 0.01-+ . When i retest it reads exactly the same, when i feed heavy for a week it reads slightly higher.

[@John_Benson]

I have a reliable repeatable method. I use the Hanna checker HI736, and also keep the calibration reference solution on hand they sell. I mix the solution up and wait the 3 min vs press and hold, rolling the vial throughout the time to get the bubbles off the glass as a film builds up when it sits. Then I perform the test 3 quick times in a row and take the average (they are always a couple ppb different). This method gets me the exact number on the reference solution every time.

[@flashkan]

If you trust icp, I would icp at the same time you do the 3 kits. Do this 3 icps in a row. See which was closest. That can stop gap till the next icp

[@codyspencer3491]

I don't experience this with PO4 testing. My Hanna UL checker, Oceamo ICP-MS, and Trident NP results are always all within 0.02 of eachother. I do experience this with calcium test kits. My Salifert, Trident, and Oceamo ICP-MS calcium tests are commonly up to 30 ppm off from eachother.

[@BIG-ES-]

I’ve tested phos once in the last 6 years. Never seemed like I was gaining anything from the test results

[@jackson6745]

I use the Milwaukee and find it in line with the ortho-phosphate readings on ICP. I think your results are fairly typical with the devices used. Salifert phosphate is for a fish only tank lol. That little Hanna egg sucks IMO. The larger Hanna is way more consistent but is essentially the same thing as the Milwaukee.

[@anthony8022]

Agreed saliferts test kit for phosphate is terrible.

[@AquariumSurge]

I have heard you for years talk about PO test kits being trash..Your not wrong, and i know you already have the PPM Hanna test kit...But 7 years ago I watched the BRS video on Phosphates test kits and the Hanna ULR was spot on with the more expensive lab grade Phosphate test kits. I have used it when dosing lanthum Cloride, GFO, or now dosing Phosphates because it bottoms out because of Vodka.. It's precise enough to make daily tweaks when I sense corals are slightly starved or dieing I know the Phosphates are probably low and the Hanna ULR will show readings of say 0 or 5. When I keep it at 30 ppb things are more stable. Do your homework but I recommend sell these test kits and get the Hanna ULR. I promise it will change your life

[@ReefBum]

I may have it somewhere.

[@don_chuwish]

I'll just stick with Hanna ULR as a consistent reference point more than a strictly accurate number.

[@douglasachaiba7885]

For me... Once it over 0.03 and under 0.2.... I'm happy. I think people complicate this hobby too much. Phosphate is a very sticky molecule .. I would acid wash my glass vials on the Hanna after every test.

[@ReefBum]

I wash my vials with water and vinegar.

[@dannymcelroy]

Try the reef factory tester, it's pretty consistent from my experience. The Trident NP is a total joke, basically an over priced nitrate tester since the phosphates are all over the place and very inaccurate and very inconsistent.

[@Malick_ibn_dinar]

As far Nitrate and Phosphate ratio that’s just a myth . I’ve been doing an experiment heavy feeding + dosing ammonium Chloride & Vodka . My tank is lot cleaner than when I use to do a lot of water change and feeding only 3 times a week with tiny portion of food . My nitrate is reading zero and I don’t plan on adding nitrate but I do feed reef roids to elevate my phosphate whenever it’s too low

[@andrefaria7284]

"Sorry, Hanna" - Tirona, Abe

[@thesmokingreefer2103]

Your forgetting the error range. Pick one kit and stick with it

[@ArlynFernandez-x7k]

multiple test .multiple margins of errors stick to one closers to ICP . Either which way even with ICP you have a margin of error. Stick to one and done