Problems with API test chart

[Cheltgirl]

They are a total pain. Hence me not using them anymore. Not that the others are great either

[audigex]

If you look down the tube in an API test it won’t give a true reading as you are supposed to view them from the side. From above it will look darker. The JBL tests are designed to be viewed from above. The Salifert tests are a combination of side and/or top so check instructions carefully.

I stand very much corrected - I'm sure they used to suggest this at some point, though - or perhaps that was just for the KH/GH kits for low readings (where the colour can be hard to see) and at some point I've taken it to apply to their kits in general

[Cheltgirl]

On the Salifert nitrate test it says to look from the top for normal result but for more accurate very low readings (for marine tanks) you look from the side. I imagine you could do the same with any test as long as you know the ratio of fluid between side on and top view.