kH testing question

[falcon]

I have a question on result interpretation. The solution color is yellow that turns blue with the first drop, then green with the second, and finally yellow with the third. What is the kH reading. Would it be 3 when the solution turns yellow, or 2-2 1/2 when there is a change in the color initially.

Thanks.

falcon

 

[MikeO]

I would like to add a follow up question what does the results mean? how do you interpert them and what range do you want the kH to be in?

 

[Blinky]

falcon - I've always counted the total number of drops needed to turn the solution fully yellow. I could be incorrect, this is how I interpret the vague instructions that came with my kit.
MikeO - KH doesn't need to be at any specific level AFAIK. I measure mine to make sure it's at least 3* (50ppm); below that level it can be hazardous to add CO2 to a tank because the pH can swing dangerously low. I think it's a good idea to buffer a tank with very soft (<2*KH) water no matter what, to keep the pH stable.

 

[MikeO]

So 5* KH is good, also should I test the tap water for the KH, and if they are diffent should I do something to bring the tap water close to the fish tank ( i am going to assume for now that the tap water KH is the same as the tanks since that where I get my water for the tank from)

 

[Aquabum]

With my kit (AP), if with the first drop the solution stays yellow, what that means is it's 1 KH.

If the solution turns blue with the first drop, then I'd continue adding drops (remembering to count each time you place a drop in the vial) until the solution finally turns yellow, thereby giving you the correct KH reading.

HTH

Lissette

 

[falcon]

So, I guess I should ignore yellow turning to blue, then to green and then yellow. In my case the correct reading would be 3(blue 1, light green 2, yellow 3)?

 

[MikeO]

mine was blue 1, light blue 2, white 3 (it looked white even when I looke down it onto a white area) white 4, light yellow 5 (I just took that 5 drops and calculated on that)

 

[anonapersona]

Falcon, yes, call that kH 3 but note in your journal (you do keep one?) KH 3 (-). It may be that it is 2.5.

What you need to do is to know if it is stable, next week is it 2.0 or 3.0? If KH is declining, you need to step up water changes if tap water is KH 3.0+ or consider additives to add buffering to keep the tank stable. Heavy fish stocking/feeding or CO2 injection to planted tanks will tend to burn through some of the buffering, as KH is lowered, you risk pH crash.

Mike), KH=5 is great, just know that if it declines you need more tap water waterchanges.

 

[falcon]

Anonapersona, yes the kH is stable. Presently I am mixing tap and r/o and that's what it comes out to. Everyweek, I do around 50% w/c. Out of tap kH is around 5. It is a planted tank that I do co2 injection(controller, pressurized).

I wanted to make sure I know what the kH to figure out the proper co2 injection. My goal was to keep the kH at 3 and keep the pH at 6.5 through co2 injection.