How do you read your api test kits accurately?


New member
I have a hard time reading these test kits I feel like im guessing on the color. It also changes depending on how much and what type of light you look at it under. How close do you hold the tube to the white side of the card? like 1"? touching? Do you do the test in just a well lit room or do you hold it under a light to determine the final color?

For anyone that has used api test kits is there another test kit that you have used that you feel like you can make a more accurate reading from? thanks


Premium Member
I use my kitchen lights (flourescent) When I stand by my tank I can't tell the difference. I hold the vial about 1/2" off the card.

I like the api kits as well as the red sea pro kits. Cheap and effective.

Reef Newb11

New member
I hold the test tube about an inch from the paper and hold it outside my window so I can view it in natural light. Might not be the best but i figure as long as i do the same thing everytime its best..


New member
i also walk outside on the patio to view in natural sunlight, i find this helps a bit when it is a vague color.....fluorescent light varies so much from bulb to bulb and is so rarely even close to natural sunlight that i dont do any reading under them when it counts.....


New member
I have the same problem with the API PH test. I feel like I'm guessing most of the time.

I've had good luck with the Salifert alk and calcium tests, and I'm thinking about trying the PH one too.


Eagles & Tigers Fan
The API calcium is pretty simple... Ive had the problem with the phosphate and nitrate tests though. Its so close between the low end levels. I just test and hope the colors dont get darker =\