KH test confusion

Slightly off-topic, but can someone explain why my KH test kit doesn't seem to work when testing freshwater ? I wanted to check water in my mother's koi pond. But the first two drops of the reagent made the solution yellow. It was never blue from the first drop.

I thought the test kit was faulty, so tried checking the water in my marine tank. Sure enough, the solution was blue at first and then turned to yellow after 8 drops.

So......why doesn't the KH test work for freshwater ? Or am I doing the wrong test and should just check PH ??

There are specific test kits for saltwater and freshwater ..... Which type is yours?

Originally Posted by nim75sg

There are specific test kits for saltwater and freshwater ..... Which type is yours?

Mine is the Sera one. The box says it can be used for both.

[BarraCuda™]

Originally Posted by hanifrez

Mine is the Sera one. The box says it can be used for both.

It simply means that the KH of the pond is too low that 2 drops of the reagent is enough to change the color.

Originally Posted by BarraCuda™

It simply means that the KH of the pond is too low that 2 drops of the reagent is enough to change the color.

Or more likely KH is zero coz the first drop alone makes the solution turn yellow

hi there. think the test kit should say that if there is any alkalinity in the water sample, a drop of the first liquid will turn it blue. if the colour change is not to blue simply means no alk i think.

cheers,
ian

Originally Posted by iantoh

hi there. think the test kit should say that if there is any alkalinity in the water sample, a drop of the first liquid will turn it blue. if the colour change is not to blue simply means no alk i think.

Or basically the water is waaaaaaay too acidic, right ???

[BarraCuda™]

Originally Posted by hanifrez

Or basically the water is waaaaaaay too acidic, right ???

It should be acidic but you will need to take the pH measurement to see how acidic.