Anyone use a colorimeter?

[aninjaatemyshoe]

I'm considering buying some colorimeters to do parameter tests, particularly nitrate and phosphate. I'd like to have much more accurate results as I just don't trust regular color changing test kits anymore. Nor do I find it adequately precise trying to decipher minute differences of color from a color card. I want something that will be able to indicate that these parameters are either rising or falling. I'm looking particularly at the Hach pocket colorimeters. Does anybody have experience with using colorimeters for doing these tests? Are they significantly more reliable/accurate than regular test kits?

 

[snorvich]

I have both. I especially find it valuable for phosphate as I cannot find an accurate test on the market.

 

[Randy Holmes-Farley]

There are many threads on these meters in the chemistry forum. Some folks love them, others have been disappointed. I would not assume that the Hanna is necessarily going to be more accurate than the best phosphate test kits, as least based on its published specs of +/- 0.04 ppm.

 

[snorvich]

For those of us who are color blind, testing has challenges.

 

[aninjaatemyshoe]

Snorvich, how does your nitrate colorimeter work? I was reading up on them and it sounds like you have to do some extra sample preparation to make them work with saltwater.

 

[md14fish]

I think HACH and Hanna are two different brands,the HACH being the better of the 2. Does anyone know a price for the HACH?

 

[TheH]

Hah, I thought you were talking about spectrophotometers. Using one of those for color-changing test kits would be hilarious.

 

[snorvich]

I am not sure how you would actually do that!??

 

[TheH]

I guess it would only work for test kits where the solution gets darker or lighter to indicate concentration. Not for kits where the solution actually changes color. In the former case, I think you would just take ABSORBANCE(Final) - ABSORBANCE(Initial) ?

 

[tmz]

I use the Hannah low range phosphate meter. I've done close to 200 tests with it and like the way it works. It works consistently well.

I am also interested in hearing reviews on various nitrate meters such as pinpoint.

 

[snorvich]

<a href=showthread.php?s=&postid=14251234#post14251234 target=_blank>Originally posted</a> by tmz
I use the Hannah low range phosphate meter. I've done close to 200 tests with it and like the way it works. It works consistently well.

I am also interested in hearing reviews on various nitrate meters such as pinpoint.

Same here. I have the nitrate meter but have problems with it.

 

[MrPike]

I have a Thermo Orion AQ4000. Its a quality colorimeter, along the lines of the Hach.

You need to keep in mind that many of the parameters that these meters test have interference from chloride so you will not get a very reliable reading. Nitrate for instance is not something I can test with my meter, at least not accurately at the low levels im interested in.

Look at the methods sheet, and it will tell you what method its using to get the reading. The thermo, hach and hanna all use the same method for testing P04, the only difference will be the accuracy of the meter taking the reading, and in this case, you get what you pay for.

 

[Randy Holmes-Farley]

Same here. I have the nitrate meter but have problems with it.

You have the Pinpoint, or something else, that you have problems with for nitrate?

 

[aninjaatemyshoe]

Is the Pinpoint a reliable device for Nitrate? I've pretty much come to the conclusion that colorimeters for Nitrate are not particularly usable for testing aquarium saltwater.

 

[Randy Holmes-Farley]

The Pinpoint nitrate meter is an electrode, not a colorimeter. I've not carefully tested it, but it seems like a good tool from the experience I've had with it. Since it gets calibrated for each use with nitrate in seawater standards, it is reliant on trusting those standards are correct. Beyond that, it seems useful to me if nitrate measurement is a goal.

 

[snorvich]

Calibration is sometimes problematic. Other than that it works well (Pinpoint).

 

[Randy Holmes-Farley]

In what way did you find it problematic?

 

[Plato]

I have a Medusa colorimeter it will test NH4, NO2, NO3, pH, PO4, and copper. It uses Sea Test/ Fast Test reagents from Aquarium Systems/ Instant Ocean. Very accurate and reliable. The only difference is that I use the Deltec Phosphate Test Kit, I find it more accurate and it has such a wide range. The PO4 for my colorimeter is from 0-1ppm. Cant test extreamly low ranges. The only bad thing is that Medusa stoped making their colorimeter a while back. It was very affordible like 250.00. I have had mine for over 8 years and is on the spot. When I test it aganst refference solutions it very accurate.

 

[Jerm77]

<a href=showthread.php?s=&postid=14251234#post14251234 target=_blank>Originally posted</a> by tmz
I use the Hannah low range phosphate meter. I've done close to 200 tests with it and like the way it works. It works consistently well.

I am also interested in hearing reviews on various nitrate meters such as pinpoint.

<a href=showthread.php?s=&postid=14252383#post14252383 target=_blank>Originally posted</a> by snorvich
Same here. I have the nitrate meter but have problems with it.

I also have problems with my pinpoint nitrate meter. don't think I've ever got an accurate read from it.

 

[Randy Holmes-Farley]

I also have problems with my pinpoint nitrate meter. don't think I've ever got an accurate read from it.

What problem and why do you think it wasn't accurate?