Confused about spectrophotometers

[reefkoi]

I've been looking for a good meter to test my tank water with.

I've looked at the lamottes, I am concerned about the levels they test at, example: potassium .0-10.0 NSW is around 380 so that wont work, LR Phosphate is .05- on up (I'd like to be able to test down near 0 ) and I think with Phos there is organic and inorganic and maybe thats something I also have to research, but basically what meter can I buy to test my water accurately? Is there an all in one or do I need to buy several?

Lets assume I budget $2500 so don't try and sell me on a $20,000 unit unless it's either that or stick with off the shelf test kits (which I hate using and want to get away from) :bum:

Or should I send my water to someone (other than AWT) that can test it?

I'm just thinking if a good lab charges $200-$300 each time I'd be money ahead if I can buy the equipment myself.

Thanks guys,
Chris

 

[therealfatman]

If all you want to use the photometer for is to test for phosphate then the low range Hanna photometer is about as accurate at the low ranges as a Hach spectrophotometerat a much lesser equipment cost. A Hach photometer would allow you to test for a few other salt water parameters is all (silica, copper). The cost of a new Hach spectrophotpmeter is at least $2000, possibly more.

Most of the tests done by a Hach spectrophotmeter are for fresh water testing rather than salt water. There are many Hach spectrophotomers on sell on ebay. The salt water parameter tests can be done on a DR/2000 or higher numbered meter. Typically all that goes wrong with them is that the UV bulb burns out. The replacement bulbs cost approximately $75.

The actual test reagents (chemical packet) used for the low range test kits for all the better phosphate test equipment, and the hanna are about $25 for 100 tests. The high range tests reagents are about equal in cost. With the Hanna brand you would need to different photometers to test both high and low range.

 

[radiata]

Chris,

I've been using a Hach 890 photometer, that I picked up on eBay, for my Phosphate and Nitrate testing (and I love it). Although the 890 can do 90 different tests, not that many of them are relevant to reefkeepers. Nitrite, copper and maybe a few others like Iron are meaniful, but things like arsenic are useless. The pH only measures for FW. The DOC/TOC requires additional equipment. Titration tests - calcium, magnesium, etc. are not relevant to colorimeter testing.

Hope this helps,
Bob

 

[therealfatman]

Are you referring to a Hach DR/890 colorimeter. I would like to own one but every Hach DR/890 colorimeter I have ever seen on ebay has sold for a very high price. Usually around 75% of their retail price of $1000. I perhaps unfairly blame the high prices on the DR/890's sold on ebay on Randy's stating that he uses one. The RC site is widely read and Randy has a very good reputation in the reef aquarium field.

 

[radiata]

therealfatman,

Yes, that's the one I have. I bought it a few years ago.

I'm obliged to pass a warning on to you - to have one repaired costs $170 an hour. My phosphate readings were high at one point, so I bought a PO4 standard solution from them to troubleshoot with. These colorimeters can be tweaked up to 10%, but mine was off by 20%. I nearly had a stroke when I called and asked about returning it. They suggested that I first buy another bag of test reagents, as mine could be off. Thankfully, they were right...

Regards,
Bob

 

[Boomer]

Hi Chris :wavehand:


First, have you heard IMAC is back, now IMACW in Calif. ? See Jake I guess there will be a 2009 but no date yet.


The issue with these is as Fatman and Bob have stated. There are very few things that one can test for where there is no Chloride ion interference. For K, any of these units, even the ~$ 9,000 DR-5000, is on .02 - 7.0 mg / l.

Or should I send my water to someone (other than AWT) that can test it?

I know they are close to you but there is a new one that uses advanced chem tests methods such as ICP. This is the method used for most ions in NSW we are interested in and not ISE probes like AWR uses.
http://labaquatics.com/


Yes, you could get yourself and ISE probe, which attaches to a pH meter that has a mV switch on it but it would be a few hundred dollors. The probe alone is $240 - $310. Then go to the U chem dept. and have them tweak if up for you so you know it is accurate in seawater.


LR Phosphate is .05- on up (I'd like to be able to test down near 0 )


LaMotte's Smart unit is to .01 ppm PO4



Phos there is organic and inorganic

Yes there is and the only unit I know off hand for this is the HACH-PO-24 that I fixed for them so it would test to .02 ppm, same for the PO-19 (PO4 only) and YUP both are test kits. And testing for the other forms of phosphate will have you throwing the kit out the door :lol: i.e., filter paper, a little burner etc.. = not fun



Bob

You are correct on that but I need to add that Nitrates is not on of those ions. Things like silica, copper, iron, phosphate do fine. I have talked to HACH and LaMotte in the past about this. You have to make up a ref std to get proper reading for NO3. Often companies say seawater till you call them and really ask them. HACH still sells a Digital Titrator for testing for CO2 in seawater, even after I proved it can't work and had it backed it up by Dr. Frank Millero, RSMAS, Dr. Craig Bingman, UWM, Ed Moka from AS and Dr. Owen Callaway from Std Methods Water-Waste Water ( the CO2 guy).

There is a Nitrate ISE meter set to seawater from Lou at American Marine PinPoint that works nice $250

http://www.americanmarineusa.com/



Fatman

Is yours any different on K ? +

And for your interests have you ever been here.

http://www.coleparmer.com/

 

[therealfatman]

I know of no Phosphate ISE probes . It would sure be nice to have one though. ISE operation is cheap. A few cents per test. I only have a few ISE probes from Thermo Orion and they are all intended for use on fresh water and waste water not marine water.

I have a couple Digesdahl units and I can definitely say sulfuric acid based digestion methods are not pleasent. As if acid isn't bad enough think of boilng acid. Definitely not a cheap equipment start up price either. Over $1,100 per unit retail, without chemicals or any accesories. They are also typically used for fresh and waste water testing.

 

[Boomer]

ISE fo K. And yes, there is no such thing as a ISE for PO4.

Something that one can do to get cheap seawater stds that will work for most ions, but not things like PO4 or NO3 which can vary, is to just get some natural seawater. TLF now is selling it with a known Salinity. One thing about NSW is it follows the Law of Equal Proportions. Meaning, all the ions in seawater are at the same ratio and are at the % in NSW @ 35 ppt as they are at some other Salinity.

Point in case. NSW is give @ K+ of 10.2 mmol/kg = 10.2 x 39.008 = 398 ppm or 407 mg / l. That means that at 35 ppt then K+ = 398 / 35 = 11.37 ppm K + / 1 ppt or 11.63 mg / l. So, if the collected NSW was say 32 ppt, then 32 x 11.37 = 364 ppm is what you should have or 372 mg/ l. Now, one could send in such a sample and a tank sample to AWT or LA to see what the K+ is. This should show you any error factor, which could now be applied to both samples and give you a good idea what the K+ is.

 

[therealfatman]

Potassium range is 0.1 ppm to 7.00 mg/L (7 ppm) by Hach DR/2100 spectrophotometer at 100 tests for $35. Orion Potassium ISE range is 0.04 ppm to 39,000 ppm. Cost is around $850 to $900 for a Potassium ISE electrode.

NSW is about 390 ppm Phosphate, I believe.

In fresh water from ground water sources your typically looking at concentrations of potassium such as:
Carbonate aquifers at 0.3 to 2.5 ppm, and sandstone aquifers at 0.8 to 4.0 ppm.

As Boomer and Randy have pointed out, there are really not a lot of water parameter tests or professional water parameter testing equipment at the professional level produced specifically for use with NSW.

 

[reefkoi]

Thanks guys for all the detailed info thats what I was looking for.
I'll follow that tesing lab link boomer, and yeah Jake told me what was happening with IMAC, I seem to end up in CA about 4-5 times a year for these shows I was really hoping it would stay in Chicago LOL I had a blast in that town...........

C

 

[Boomer]

Fatman

Yah, those Orion's are a arm and leg and great probes

NSW is about 390 ppm Phosphate, I believe.

I have done this, it is not from enough coffee

You mean ~ K+ = 390 ppm.

Phosphate = ~ 0.005 ppm but can be much higher. It also does not follow the LEP, as most other ions do as it is a "nutrient", like C and N

The NSW Copenhagen std is NSW is give @ K+ of 10.2 mmol/kg. Here is a great site fof this. Click on the element and it will eve give you plots of ions mol as a function of depth.

http://www.mbari.org/chemsensor/pteo.htm


Chris

I was really hoping it would stay in Chicago

I agree but like the Calif idea. Jim and I from theflterguys were looking for a place to go in Calif since IMAC was gone and now we have a Calif one to go to. The other thing is Chris from Lumatek is there in Calif and may be easier for him. I know, I know he is just one guy :lol:

 

[radiata]

<a href=showthread.php?s=&postid=13938400#post13938400 target=_blank>Originally posted</a> by Boomer
Bob

You are correct on that but I need to add that Nitrates is not on of those ions. Things like silica, copper, iron, phosphate do fine. I have talked to HACH and LaMotte in the past about this. You have to make up a ref std to get proper reading for NO3. Often companies say seawater till you call them and really ask them. HACH still sells a Digital Titrator for testing for CO2 in seawater, even after I proved it can't work and had it backed it up by Dr. Frank Millero, RSMAS, Dr. Craig Bingman, UWM, Ed Moka from AS and Dr. Owen Callaway from Std Methods Water-Waste Water ( the CO2 guy).

There is a Nitrate ISE meter set to seawater from Lou at American Marine PinPoint that works nice $250

http://www.americanmarineusa.com/

Boomer,

I think you've rained on my parade. Is the Hach 890 that significantly off on NO3 in seawater that I should consider the American Marine Nitrate ISE meter in order to get greater accuracy? How difficult is it to make up an appropriate reference standard? Would you know where I can find any instructions for making the appropriate standard or know of a source for buying it?

Thanks in advance,
Bob

 

[Boomer]

No Bob I do not know how far off. HACH asked me long ago to do some work for them on it and I said sure and for free, just send me a meter and this was the cheap Pocket II ~ $200. They said no, you have to buy the meter. This was after I fixed their PO-19 PO4 kit, so it could test to .02 ppm, which I also did for free. I said buy it :eek2: ..... you guys are nuts , so stick it :lol:

This what I would do for shits and giggles for now. Get some table salt and measure out 36. 5 grams, this will be close to seawater. Add it to 963. 5 ml of water. Get some of this below..............

» Nitrogen-Nitrate Standard Solutions as NO3-N (NIST), 1 mg/L, Bottle/500 mL **and test your meter


or

» Nitrogen-Nitrate Standard Solution as NO3-N (NIST), 10 mg/L, Bottle/500 mL**and test your meter

http://www.hach.com/hc/view.documen...NU1EQXdNelV5Sm1kMVpYTjBTRmxQUVE9PUJGQXhNVA==|


And do something like this. 9 ml of your salt water std and add 1 ml of the 10mg / l. The meter should read 1 ppm NO3. For the 1 mg / l NO3 std it should read 0.1 ppm with 9 ml of SW. You can see where I'm going here.

There are no Seawater stds unless you have crap loads of money for a little bottle, ~ $200 - $400

Go here for that
www.seawatersolutions.com

http://www.seawatersolutions.com/nutrient-standard-solution-nss-23-p.asp



The Pinpoint is only accurate to +/- 1 ppm

Or take a split sample of your water and measure 1/2 of it with your HACH. Then send the other 1/2 sample here

http://labaquatics.com/


See how they compare.

or

Buy this article or get someone to get it for you

Preparation of the standard solutions of nitrate and their application to seawater and freshwater
http://www.springerlink.com/content/l1n8366371g60j27/

 

[radiata]

Hach Colorimeter SW Nitrate Testing

Hach Colorimeter SW Nitrate Testing

<a href=showthread.php?s=&postid=13952105#post13952105 target=_blank>Originally posted</a> by Boomer
No Bob I do not know how far off. HACH asked me long ago to do some work for them on it and I said sure and for free, just send me a meter and this was the cheap Pocket II ~ $200. They said no, you have to buy the meter. This was after I fixed their PO-19 PO4 kit, so it could test to .02 ppm, which I also did for free. I said buy it :eek2: ..... you guys are nuts , so stick it :lol:

This what I would do for shits and giggles for now. Get some table salt and measure out 36. 5 grams, this will be close to seawater. Add it to 963. 5 ml of water. Get some of this below..............

» Nitrogen-Nitrate Standard Solutions as NO3-N (NIST), 1 mg/L, Bottle/500 mL **and test your meter


or

» Nitrogen-Nitrate Standard Solution as NO3-N (NIST), 10 mg/L, Bottle/500 mL**and test your meter

http://www.hach.com/hc/view.documen...NU1EQXdNelV5Sm1kMVpYTjBTRmxQUVE9PUJGQXhNVA==|


And do something like this. 9 ml of your salt water std and add 1 ml of the 10mg / l. The meter should read 1 ppm NO3. For the 1 mg / l NO3 std it should read 0.1 ppm with 9 ml of SW. You can see where I'm going here.

There are no Seawater stds unless you have crap loads of money for a little bottle, ~ $200 - $400

Go here for that
www.seawatersolutions.com

http://www.seawatersolutions.com/nutrient-standard-solution-nss-23-p.asp



The Pinpoint is only accurate to +/- 1 ppm

Or take a split sample of your water and measure 1/2 of it with your HACH. Then send the other 1/2 sample here

http://labaquatics.com/


See how they compare.

or

Buy this article or get someone to get it for you

Preparation of the standard solutions of nitrate and their application to seawater and freshwater
http://www.springerlink.com/content/l1n8366371g60j27/

Boomer,

Thanks for the reply and methodology.

It occurred to me that since the PinPoint Nitrate meter is designed for saltwater, that I should be able to use their calibration solutions to test the Hach 890 for comparative accuracy. I think this would be a valid test if their solutions are made with saltwater. Any thoughts?

Thanks,
Bob