So this morning I awoken to a half eaten shrimp so i decided to test the water as I did see a baby shrimp not so colourful. Anyway I tested it all and all came back good except for my ph it was royal blue very dark almost instant on the API test. I started to freak because I don't have any water of ph 6.5 to transfer. Anyway I decided to Re test my ph and it came back fine. I did another test again and was ok to. Anyone else experience this before?

Dirty test tube..... I'd say

10 minutes ago, inverted said:

Dirty test tube..... I'd say

Thanks, I do rinse them before using though

51 minutes ago, Mitch91 said:

Thanks, I do rinse them before using though

I rinse mine with RO water ( as it closely matches my tanks water ) and let them thoroughly dry.
I don't know if this is useful to you or not :)

It might seem silly to even mention, but was the cap thoroughly washed (multiple rinses with good agitation) too?

Other things I've done - too many drops (one snuck by too fast, I zoned out, I forgot), used the wrong test fluid.

12 hours ago, Mitch91 said:

 I do rinse them before using though

Did you rinse in tap water?

Cause tap water is pH 7.8 - 8.0 depending on where you are.

That might have contributed to the high pH reading.

I often get this happening with tests of ALL makes. I dab the dropper on tissue first to clear the dropper of old drop fluid and ignore the first test, usually second onwards are accurate. I don't test that often and rinse test tube in tank water before and after. 

I also find different makes give different readings which isn't helpful!

That's why I use a pH pen now. More accuracy and less variation.