Api Kh/gh Test Kit

[celaeno]

i'm using the api kh/gh test kit.

for the kh test, do i stop adding drops after seeing the slightest yellow tint?

for the gh test, do i stop adding drops after seeing the slightest green tint?

 

[SJ2K]

Doesnt it come with instructions?

 

[doresy]

Put in the amount of drops it asks you to. Give it a shake then compare to the chart after 5 minutes,

It's all in the easy to follow instructions

 

[Bignose]

Put in the amount of drops it asks you to. Give it a shake then compare to the chart after 5 minutes,

It's all in the easy to follow instructions

No. This advice is very wrong. It's not an "add x amount of drops test" it is a titration test where you count the number of drops you have to add until a color change occurs.

To the OP. You want to add drops until you start to notice some temporary color change, though the solution probably goes back to its original color. After this starts to occur, you are going to only add one drop at a time, and after each added drop, you will put the cap on and then give the vial a shake. Only when the entire vial changes to the second color, that's when the test is done. When the entire vial changes to the second color, the titration is complete. If you stop when the color just first changes, but then changes back, you haven't completed the entire titration.

 

[pauly]

It's not as easy as it sounds though, especially the Gh test. The change in colour isn't as obvious as the Kh test.

 

[Essjay]

The colour change is easier to see if you remove the lid, hold the tube over something white and look down into the tube. It makes the colour look more intense - very useful if you have soft water like we do. The colour changes after only a couple of drops when it is very pale and hard to see.

 

[pauly]

Cheers essjay, I'll give that a whirl.