pH dropping -hello winter

[asylumdown]

hmmmm, i might be out to lunch, API might test for carbonate alkalinity directly. I haven't used it in years, what colour is the reagent when it comes out of the bottle?

[Reef Pilot]

Originally Posted by asylumdown

hmmmm, i might be out to lunch, API might test for carbonate alkalinity directly. I haven't used it in years, what colour is the reagent when it comes out of the bottle?

It is pink first, and then turns purple/blue.

[asylumdown]

hmmm, then nope it's still measuring total alk, even though the box says it's measuring KH, which is not the same thing and is usually expressed in different units (meq/L). I can't figure out what indicator they're using, but what's in your bottle is basically just an acid and an indicator that changes colour once all the buffering capacity has been consumed and the solution suddenly turns acidic. Might be litmus.

I just searched reef central and found some posts from Randy Holmes where he found that the borate alkalinity test from sachem wasn't all that accurate so he recommends not doing it. If you've been doing what you're doing for two years I'd say you're probably fine. My case was likely an extra special case of being 'extra special'.

[Reef Pilot]

Originally Posted by Reef Pilot

It is pink first, and then turns purple/blue.

Whoops, I was thinking of my Ca test kit (2 part), which is also API.

The API KH test starts off blue, and then turns green/yellow and uses only 1 reagent.