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Reading and determining the color of test kit results.

Vincerama2

Vincerama2

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OK, so I did a nitrate test on my water (it was off the chart) and as I was googling around, one person mentioned that you are supposed to look DOWN the test tube not at the side of the test tube ... what?

I'm not sure if that's try, or maybe it's only true for SOME test kits.

But anyway, I can't tell "Orangish red" from "Reddish orange" from "slightly orange and red". Ditto with greenish yellowish blueish, etc.

I was thinking that .. taking a digital photo and then using MS Paint or photoshop or something to compare the colors (ie looking at the color graph OR just cut and pasting the sample color onto the color chart to just get a better comparison might be a good way to do it.

Or ... do I not really care. IN terms of nitrate, it's clearly yellow if it's less than 10, and red of various hues for higher amounts and I'm at 219 which is beyond the scale, so I'm really just looking for anything yellow.

How do you guys do it?

V
 
Oh another question. Does the "depth" of the sample change the color? I was thinking that a shallow glass container, like a petri dish could be used to pour the resulting sample in and then this could be placed on top of the color chart to read.

For me, looking through the round test tube gives me different looking colors based on where the light is.

V
 
I've been using Salifert, and contemplate between the middle color change or complete color change. It's like a difference of one to two drips, which isn't too significant. I think the difficult part is putting the reagents, especially the Calcium one. When I tilt the bottle, it does one drip without squeezing, so I'm not sure if it's a full drip or partial drip.

The Alk and Mag drop bottles are smaller and easier to drop. Just have to tap it a few times to get air bubbles out.

I just use a white background and look from the side.

I've been reading about magnetic stirrers, not sure if it makes it more accurate, but seems kind of cool not needing to swirl the tubes by hand.
 
Depends on the test kit. If it has comparison test tubes where you have a tune filled only with tank water and you compare it with the tested sample by placing on a color wheel or chart, then yes. You are supposed to look down at the sample.

If it is just a chart you compare it to, I just place it against a white background and check.

I of the reasons I like colorimeter checkers is I don't have to deal with what color is it really!?! Plus I have a mild case of protanomaly so purples and shades of red or green are a hard read for me.

Numbers work.


Sent from my iPhone using Tapatalk
 
+1 for hanna.

The only test I use that require color matching is salifert nitrate which is waaay easier to read that different shade of orange on the API kit. I only use API for fresh water as it is useless at lower range.
 
Depends on the test kit and what your readings are. On the Salifert nitrate test kits, you look down on the sample if you have high nitrates (set your sample on top of the chart). If you run really low nitrates, like I do, then you look at the same from the side. I just hold my sample on the side and then slide the chart behind it to get a reading.
 
I'm using API. However in my case it's currently fine since I'm off the chart and if I can see ANY yellow, then I know something is working.

However, I'm wondering if we can get our computers (or phones) to do the color comparison for us. I'll give it a try later. I did take some pics, but with flash, there is too much shininess from the test tube, and I'll need to find a nice white light.

V
 
yellojello said:
I've been using Salifert, and contemplate between the middle color change or complete color change. It's like a difference of one to two drips, which isn't too significant. I think the difficult part is putting the reagents, especially the Calcium one. When I tilt the bottle, it does one drip without squeezing, so I'm not sure if it's a full drip or partial drip.
Click to expand...

Hah! I always thought I had a defective bottle. This drives my absolutely crazy with the Calc test.
 
Bruce Spiegelman said:
Hah! I always thought I had a defective bottle. This drives my absolutely crazy with the Calc test.
Click to expand...

If you squeeze the bottle before inverting it and letting go as you invert it, it creates suction and prevents the liquids from dripping out before you have it fully inverted.


Sent from my iPhone using Tapatalk
 
I tend to measure it in the way that looks like the least nitrates.
:rolleyes:

Yes, it is confusing, everyone does it differently, and the API instructions do not say if it is supposed to be down or sideways.

Think of it as another good reason to not chase numbers.
 
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