Phosphate checker question?

[lnevo]

I just order the Hanna phosphate checker but I think I made a mistake...

My phosphates have been 0.02 on a Red Sea Pro test kit. I wanted the digital so i could get a better resolution and check quicker.

So while I'm waiting I went to look at the specs etc and now I'm wondering if I should have ordered the ultra low phosphorous checker...

So my question is for those with already low phosphate who may have this tester, will this checker be good or should I flip it and get the phosphorous model?

The resolution is .01ppm but the accuracy is +/-.04ppm

Should I flip the checker and get the ultra low phosphorous? or do you think its sufficient? Was I better off just doing the RSP test?

 

[duke62]

Difference in checkers will be like .02 to .03. I watched it on you tube. Not much of a change. So if your PO4 is at .02 your PO4 needs to come down

 

[Widdy]

While the ULR might be slightly more accurate, it requires conversion to get PPM.

http://www.manhattanreefs.com/forum/chemistry/116018-hanna-phosphate-phosphorus-ulr-checker.html

I wish I can maintain a constant level of .02 PO4, unless you mean .20, Duke :/

 

[lnevo]

.02 is the lowest the RSP test goes before 0 and its hard to judge between them so I err on the .02 side.

I'm fine with either if the hanna will read 0 or .01

I thought the goal was to be below .03

Whats the best way to measure below .02? Is there a low low range i can do on either test with more dillution?

 

[Boomer]

There are no test kits or meters that can detect below 0.02 ppm to include $800 meters. All of them have a +/- the best is the LaMotte @ +/- 0.02 ppm but you never see these +/- on test kits, just meters and kits are worse. The only benifit in meters is many have issues with reading color comparisons and kits are more subject to user error but so are some meters, especially Alk meters.

People have the bad idea that because it is a meter it MUST be better <--- lot of BS there. And the answer to that is almost all meters are based on FW stds, not Seawater std and so are most kits. Only Salifert has made efforts to make their kits based on seawater. The Sodium and often Chloride ion raise hell with meters and is referred to as the "Salt Effect Error". Some meters are not affected by this, such as Phosphate, Silica, O2 and Iron, while others are, pH, Ca++, Mg++, NO3, NO2, NH3, NH4, O3, CO2 and Alk and a host of others. And so are many kits. Then there are the crappy reagents that come with many meters and kits. You have to remember here, you are dealing with aquarium kits/meters and not Lab grade kits/meters.

 

[Boomer]

A reading of 0.01 is meaningless when the accuracy is +/- 0.04 <--- that means, if the meter reads 0.04 the actual level is somewhere between 0.00 - 0.08 or if it reads 0.09, somewhere between 0.05 - 0.13 ppm and you have no clue where.

 

[kres1024]

A reading of 0.01 is meaningless when the accuracy is +/- 0.04 <--- that means, if the meter reads 0.04 the actual level is somewhere between 0.00 - 0.04 or if it reads 0.09, somewhere between 0.05 - 0.13 ppm and you have no clue where.

Well that's still a better ballpark reading to have than if the meter was showing 0.10 or higher

 

[lnevo]

Think I'm more confused now than before..

So what I'm getting is there is no way to measure less than 0.02ppm and it wouldn't be any different with the ULR Phosphorous checker either.

Am I good with a .02 or should I be aiming for completely 0. Will the hanna even register to 0 (which obviously could still be .04)?

Just wondering how best to gauge moving forward and whether or not to trade the checker or not. It would be a great deal for someone since it was the BRS doorbuster price

 

[Boomer]

Pretty much it with kits or meters, ball park reading. Besides, people need to stop chasing numbers. This is my buddy Richard Ross tank, PO4 @ 0.90 ppm

 

[lnevo]

Not trying to chase numbers so much as monitor. I'm switching to high capacity GFO and wanted to more conveniently monitor to see when to change the media rather than changing every X weeks. I guess I'll just see how it works for me and go from there...

 

[Boomer]

The Hanna ultra, forgot about that one, has a resolution = 0.001 ppm and Accuracy ?5% of reading ?10 ppb

10 ppb = 0.01 ppm

So, you take 5 % of the reading and add 0.01, let's say 0.008 ppm

So, (0.008 x. 5 %) + 0.01 = +/- .0104 ppm

So, that 0.008 is somewhere between 0.00 - 0.0184 ppm


IMHO a waste of money @ $75. Having ultra low PO4 DOES NOT EQUAL SUCCESSFUL TANK. The success of a tank is the guy in the mirror. Many successful reef tanks have high PO4, look at the post above @ 0.90 ppm PO4.

 

[kres1024]

And what test apparatus did he use to determine that he has 0.90?

 

[Boomer]

California Academy of Science: Stienhart Aquarium Chem Lab, with a HACH DDR Spectrophotometer, his own kit testing and AWT. He works at the CAS:Stienhart, this is him home tank. IIRC, he has also sent samples to ENC. Most seem to range from ~ 0.70 - 0.90 ppm.