Salifert Dissolved Organics test?

[mkirda]

In looking for a retailer that stocks Hach test kits (If anyone knows, please post it- I've wasted my lunch hour already!), I noticed that Salifert is marketing a Dissolved Organics test kit.

Is this test worth anything at all?
I was under the impression that in order to measure organics, you needed to heat the sample to temperatures that you could not normally achieve at home.

I also vaguely remember someone giving a lecture back at MACNA 8? (KC) where he described using potassium permanganate as a crude measure... As the memory serves me, you'd mix up a known solution of Potassium permanganate, then drip in x amount of drops into a sample of Y size, then measure the time it takes to go clear. Or something similar to this...
Is this potentially workable?

Regards.
Mike Kirda

 

[randy holmes-farley]

I tried to use the Tropic Marin organic test (but it failed). I've never used the Salifert test, but others have. Here's a long thread where we discuss organics in tanks:

http://www.reefcentral.net/vbulle tin/showthread.php?s=a7393893c8dbcff0a9b3fca9c9d57e97&threadid=51034&highlight=organic+salifert+tropic+marin

Hach tests can be obtained directly from Hach (www.hach.com).

IMO, you can probably use organic phosphate as a measure of organics in tank water (if what you want is a relative comparison), and that proposal is discussed in the thread above.

[ April 19, 2002: Message edited by: Randy Holmes-Farley ]</p>

 

[CraigBingman]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by mkirda:
<strong>In looking for a retailer that stocks Hach test kits (If anyone knows, please post it- I've wasted my lunch hour already!), I noticed that Salifert is marketing a Dissolved Organics test kit.

Is this test worth anything at all?
I was under the impression that in order to measure organics, you needed to heat the sample to temperatures that you could not normally achieve at home.

I also vaguely remember someone giving a lecture back at MACNA 8? (KC) where he described using potassium permanganate as a crude measure... As the memory serves me, you'd mix up a known solution of Potassium permanganate, then drip in x amount of drops into a sample of Y size, then measure the time it takes to go clear. Or something similar to this...
Is this potentially workable?

Regards.
Mike Kirda</strong><hr></blockquote>

Mike,

Regarding resellers of Hach test kits: Hach doesn't give them enough of a break to make that a viable proposition, so you will wind up paying less if you order directly from Hach.

http://www.hach.com/

I'm unfamiliar with the hobby test kits for "dissolved organics." The problem is that "dissolved organic chemicals" can encompass literally any and all organic molecule that gets dissolved in your tank water. They are not a cohesive group, and it is extremely difficult to develop an economical test methodology for measuring them. Actually, it is even difficult for chemical oceanographers to measure them accurately.

I had a couple of articles in the printed issues of Aquarium Frontiers on measuring water "color" which *may* track with the overall TOC. There are commercial test kits, but one of the most sensitive tests you can run is to simply put fill a white five gallon bucket with water from your tank. If appreciable concentrations of humic compounds are present, the water will be yellowish.

I suspect that the organic phosphate test kit will tell you more about the concentration of phosphate than the overall TOC concentration. In natural waters, total phosphate tends to be 2-3x higher than inorganic phosphate. If anyone has seen any significant deviation from that ratio in a reef tank, I'd love to hear about it. It is basically what I've seen in all the systems I've measured.

Craig