When to measure kh and gh in a tank

[subramn]

I have purchased the API Test kit to measure gh and kh, but not sure when to do it, whether in the tap water or change the water in he tank, add water conditioner, test or just change the water in tank, before adding water conditioner measure the gh and kh.

any guidance

[Dawn T]

To my knowledge, water conditioner doesn't affect KH and GH. I test my tap water occasionally (they sometimes change the system on a seasonal basis) so I know the parameters for it (and thus, how it could affect my tanks). Otherwise, I test the tank water itself to monitor things.

[subramn]

@Dawn Turner Thanks, so just get the tap water and test it. what is ideal for guppies?

[Dawn T]

@subramn I'll let others address that question. I've never been a guppy keeper. Swordtails are my livebearers of choice (with platies thrown in the mix now and then), and I don't remember what guppies need compared to swords/platies. @Cory?