How are you testing phosphate?

[rishma]

Time to get a new phosphate test/kit. I was thinking folks in this forum would be paying more attention to phosphate than most, so what are you using and what do you recommend?

Hanna Checker?
Ultra low range hanna checker?
salifert?
elos?
Hach?


Thank in advance for the advise.

 

[cpllongjk]

What kind of tank do you have or plan on having. If you want SPS and want them to be beautiful get a hanna checker, but you can get away with using someone that has one local. Once PO4 is stable the only way you can raise it is by not doing water changes or over feeding. My suggestion is if you dont want to spend the money on a hanna checker, get a routine down (feeding and waterchanges) before adding sps and then ask to use a local reefers. IME the test kits by ELOS and Salifert are very innacurate. However elos has a new professional kit that may be good, Ive never used it though.

 

[cpllongjk]

Forgot to add, once you get po4 stable, you can tell how high po4 is by observing your tank. Elevated po4 will tend to dull your sps and also cause green algae to form on sand/rocks/glass.

 

[offroadodge]

hanna meter

 

[Cultivatedcoral]

Hanna

 

[rishma]

I keep a mixed reef including SPS. Colors are nice, though not outstanding. I have been monitoring phosphate and nitrate for the last several years through observation only (SPS colors, growth, frequency of wiping algae from the glass, etc). not very Precise, but it has worked well even though I am dosing carbon sources. I am hesitant to get any more aggressive with the carbon dosing until I have a better handle on actual values.

for hanna checkers, what is the opinion on the low range (ppm)HI713 vs the ultra low range (ppb) HI736. I now it would be nice to have ppb readings but I am concerned about the accuracy/repeatability.

Thanks the help!

 

[BuckeyeTodd]

I started a thread in the reef chemistry section on this topic a couple of weeks ago, and the chemistry majors decided that there isn't a test kit on the market that meets our needs due to the interference of all the stuff in our water. Personally I dedided if there isn't any concrete difference, why spend the extra money and got the hanna checker

 

[iap]

I thought the little hanna egg checker was innacurate as well. Or are you talking about using the biv blue hanna checker?

 

[rishma]

I was referring to the new $50 checkers HI713 (ppm range) and vs the ultra low range HI736 (ppb).

I found the thread in the reef chemistry forum. I guess I can live with inaccurate if it is reasonably precise. I guess I don't care if I am at 5 ppb or 10 ppb, both would be good. The problem is, my salifert kit just read 0 all the time. I just don't buy it. I'd like some thing a little better than that.

 

[4x2x2]

I was using a D-D merc but having to ask second opinion (colours) find the hanna weekly testing my out flow ten times better !

 

[wickedfish]

Yeah the lil green eggs work good ( 50$) and it's pretty quick on the results and it's digital.

 

[karsco]

Hanna little green egg as well, works pretty well...

 

[Thairun]

Hanna little green egg as well, works pretty well...

+2...........am in control.

 

[iamwrasseman]

test kit $25 somewhat tough to use and read
Hanna meter or ultra low range $60 or less but you will be purchasing reagent packs at $10 for 25 , easy to use ,very easy to read
to me its a no brainer as you have thousands invested and whats a few extra bucks for accuracy of such an important parameter ?

 

[alessandro]

Here in Italy most of the reefers use Hanna meter (or checker) with Merck or D-D Or Elos Ultra or Tunze or Rowa (are all the same) reagents.
The Hanna photometer is very good but Hanna reagents aren't.
If you want a reliable test with Hanna just add to vial test 10 drops of reagent A and 1 spoon of reagent B, shake for 1 minute and put in Hanna...it works also in PPB checker (HI936).
You don't care if in Merck and the others you mist use a 20ml vial, it is ok also in the 10 ml Hanna vial....tested a lot of time.
Yes, I know, you need Hanna AND the other test but it is the only way to have a reliable Hanna test.

 

[rishma]

Thanks all for the replies. I looks like the Hanna checkers have gotten everyone else excited, too.

One of the main reasons I have not purchased one is based on a thread in the reef chemistry forum. A chemist sent out some standards to four reefers to have them tested. The results are summarized below. In a nutshell, the ULR meter did not perform too well in the range we are interested in.

It could be the meters, reagents, or both. I don't know. Very discouraging.

I thought I would post a bit of a summary as results are kind of trickling in. Phosphate standards were made at concentrations of 1,0.1, and 0.01 ppm in MilliQ water. They were sent to four individuals. These are the results for the neat standards, which would represent the 'best case scenario', i.e., no matrix effects etc.

1 ppm 0.1 ppm 0.01 ppm
0.90 0.09 nd
0.95 0.06 nd
0.93 0.06 nd
0.94 no measurements

nd = not detected, no measurements = still waiting on results

So, these meters seem to work fairly well at 1 ppm, giving both accurate and precise results. However, at 0.1 ppm, things start to break a bit even in a neat solution. With the 0.01 ppm standard, phosphate was not detected by anyone.

I had someone due a matrix effect experiment where they diluted the 1 ppm standard with an equivolume amount of their tankwater (which was reading 0). They got a reading of 0.06 ppm. It should have been at least 0.5.

So, I think the take home message is that these don't appear to be too reliable on the low end and are also subject to spurious results due to matrix effects. Keep in mind this is a $50 hand held meter. However, I think the manufacturer should be less ambitious w/respect to the advertising of the meters capabilities. If you are measuring phosphate because you are interested in levels compatible with SPS (less than 0.05 ppm), I am not sure this is the best way to go.

http://www.reefcentral.com/forums/showthread.php?t=1928707&page=2