Hanna Phosphate / Phosphorus accuracy

[mehaffydr]

So I have been going crazy trying to lower phosphate and it just seams like I'm getting nowhere. I have a 1000 gallon tank with about 1200 gallon total volume. Just some quick background I started this tank with a mix of about 200 lbs rock from my old system, 200lbs of Marco and about 200 lbs of dry rock purchased from other reefers. I did minimal testing the first few months other than Calcium, ALK, PH, Salinity and temp. Just figured things needed to have time to balance out and I needed to exercise patience. After about 3-4 months I bought Hanna ULR Phosphorus tester test in PPB. It was showing crazy high Phosphate. It was constantly showing 200PPB which is its max and per their conversion chart that's at least .613 PPM phosphate. So I tried a few things Like GFO which had no effect so then Phosphate E, which also had no effect. I was going crazy wondering where these Phosphates came from but because I did not know the background of all the rock I thought that might be it.
I only have 5 fish in 1200 gallons so not from feeding.
So I bought the Hanna LR Phosphate tester and tonight tested with that and what do you know .03PPM
So now my question is do the Hanna testers go bad? could there be something blocking the light? how do I know whats the real number? I need to either buy a Salifert test kit and compare or send off Triton ICP Test sample and see what that shows?

Any thought or incite is appreciated.

 

[DrZoidburg]

.613 +/- % error is UlR phosphorus max range. If done right the one I got was so accurate it scares me. This one has a less % error than the phosphate one I would believe the phosphorous one first. There is a possibility of reagents going bad, or things interfering. I would think it would be more likely your rocks are actually putting it out, or interference, mabey other reasons.

 

[mehaffydr]

.613 +/- % error is UlR phosphorus max range. If done right the one I got was so accurate it scares me. This one has a less % error than the phosphate one I would believe the phosphorous one first. There is a possibility of reagents going bad, or things interfering. I would think it would be more likely your rocks are actually putting it out, or interference, mabey other reasons.

Sorry I did fail to mention a couple things because the post was getting long. I have done many tests with different reagent packs with different lot numbers. and so tonight I took the sample that tested at 200PPB and pulled out 1 ML added that to a clean vial and added 9 ML RODI. It still tested 200PPB

 

[DrZoidburg]

Possible for a problem checker, or reagent then I'm sure they will help.

 

[DrZoidburg]

More likely the checker I would think using different lot numbers.

 

[mehaffydr]

The other thing I was wondering looking on BRS website they have calibration kits for some hanna testers but I dont see one for the ULR Does anyone know if Hanna offers one?

 

[mehaffydr]

More likely the checker I would think using different lot numbers.

Thanks for helping this is just puzzling me. I have done more than 50 test over the last few months and I just thought I had crazy high Phosphate but now I'm not sure.
I bought some of the ICP tests on Black Friday I think tomorrow I am sending one off.

 

[DrZoidburg]

The other thing I was wondering looking on BRS website they have calibration kits for some hanna testers but I dont see one for the ULR Does anyone know if Hanna offers one?

They do have these standards they call them. First I would check a couple other things. Like silicates, or arsenic for example, can interfere with the reading.

 

[Shirak]

The other thing I was wondering looking on BRS website they have calibration kits for some hanna testers but I dont see one for the ULR Does anyone know if Hanna offers one?

They are standards. They are not calibration kits... They will tell you if the tester is broken by not giving the correct value to the standard

 

[mehaffydr]

They are standards. They are not calibration kits... They will tell you if the tester is broken by not giving the correct value to the standard

OK thanks at least I would know. If they were kinda close it might make sense but there so far off its puzzling. I am sending a Triton ICP sample tomorrow. Well see what they think.

 

[jda]

If you have non-expired powder, cleaned the vials perfectly and waited the three minutes, then I think that Hannah Ultra Lows are pretty good. I don't expect a $50 hobby tool to be awesome, but I have found them consistent and reasonably accurate - which is all that you need.

Most people that have issues have crud all over the vials and stuff, only used one vial or did not wait the three minutes.

 

[mehaffydr]

I regularly clean and rinse the vials with RODI. I clean them after taking water sample and after mixing reagent so yes my vials are clean. The biggest problem I see is the vast difference between the two testers.

 

[ReefGeezer]

The unit could have gone bad. BUT... Etched vials are what throws mine off. I use one vial, cleaned with RO/DI, and dried with a microfiber towel. When I start to get results I don't trust, I replace the vial. BRS has them for cheap.

 

[Sleeping Giant]

Buy the 25 pack of new vials from Hanna themselves, way cheaper. Almost the same cost of 2 vials from BRS

 

[X-37B]

Try this first.
Change the battery.
Also unplug the connection and make sure its full connected.

If that does not work I would think the ulr is bad.

I have both also and use the ulr 99% of the time

I actually tested po4 today.
LR was .03
ULR was 30ppb or .092

LR accuracy is +- .04 and my LR always reads lower by some amount than the ULR.

They are not bad for hobby kits.

 

[mehaffydr]

So I took a microfiber cloth and wrapped it around a small dowel rod. I put just a small amount of windex and cleaned the inside of the checker. I then did another test and it showed 44 PPB Phosphorus which translates to .135 PPM Phosphate. i will do some additional testing but this seams to maybe be the problem.

 

[Shirak]

So I took a microfiber cloth and wrapped it around a small dowel rod. I put just a small amount of windex and cleaned the inside of the checker. I then did another test and it showed 44 PPB Phosphorus which translates to .135 PPM Phosphate. i will do some additional testing but this seams to maybe be the problem.

a little vinegar will help dissolve deposits. I rinse my vials several times after testing and store full of RODI. Even with that I sometimes clean the inside of the vials with a white cloth and they come out tinted. Theoretically if you are using just the one vial and orienting it facing the same way from start to finish, the checker should take into account any tint on the glass as it zero's in the first step.

 

[dvgyfresh]

I would run a test using rodi water if phosphate shows up something’s up