Results 1 to 4 of 4
07-23-2014, 10:25 PM #1Member CoryCat
- Join Date
- Jun 2014
API Master Kit, how to use the colour chart correctly?
4 months into my first tank and I still don't think I use the colour chart correctly... At least I am not sure if I am or not (lost instructions
So for example I want to test my nitrates, I first did a test on my tap water and it came up showing 0, clearly yellow in colour.
I test my tank and I get an orange, problem is I am not sure whether I am looking at 10ppm or 30ppm or somewhere in between.
There is no natural sun light in the room at all, normal light fixtures. Do I hold the card up to the light with the card separating myself from the light or with me separating the light from the card.
Also, do I put the test tube touching the white on the card or like a bit away from the card but still in front of the white portion?
Doing these things results in lighter or darker shades of orange which is confusing :s
07-24-2014, 01:53 AM #2
You might find it helpful to use a white wall as background (or a white piece of paper), if you have a wall painted white somewhere in the house. That will help show the colour a bit better. I hold both card and tube against a white wall, beside each other, and move the card up or down along the tube - perhaps if the colour patches are below the bottom of the tube while you are comparing it will be easier to pick out the closest shade.
I wouldn't worry too much about the shades being different when you move things around. When you get a result that matches a colour patch well (it doesn't matter which one) remember what you did, maybe even repeat it for confirmation, and just do it that way the rest of the time. Consistency is more important and more indicative...if you do it the same way all the time and get a different colour once, you know its the sample and not how you did the test. If you waffle and kinda do it a different way all the time, you will never know if a change is due to the water or due to how you held the card that day.20gal long planted community
07-24-2014, 02:36 PM #3
Put the test tube touching against a white background. I know there can be slightly shadowed areas on the test tube since it is a cylinder. You need to look at the area of the test tube that is not shadowed, generally not around the curved edges.
07-24-2014, 08:26 PM #4Senior Member Flowerhorn
- Join Date
- Oct 2006
- South Central Maryland- Washington DC Suburbs
Lot of people have this problem including me. I just put the test valve up to a bright light.currently setting up a 125 gallon