kh lower in tap

[wickerman]

i tested my tap water today and the KH was 1
In the fish tank.(which uses the same water) the KH is 3...
how can this be?

is tap water just drawn high in c02??could that be whats ate my buffer?

also my taps water po4 level is 3..is that high enough to drop my ph levels,like acting a a ph down buffer?

 

[carpguy]

Are you adding CO2?

How often do you do water changes and how large?

Tapwater is often higher in gasses, including CO2, but that's not taking down your buffer. Likewise, the phosphates shouldn't mess up your KH readings (althought that's high for phosphates).

KH will drop over time because of the normal metabolism of the tank unless its replenished on a regular basis.

 

[RTR]

Unless there are carbonate-bearing rocks, the substrate, or decor such as coral, shells, etc.in the tank.

 

[wickerman]

i add co2 by a simple bell jar..ive got co2 of about 14ppm and 2.5wpg of lights(which i hope will both level each other out)

i have just gravel and bogwood in the tank
i water change 25% each week

 

[carpguy]

Sorry, read the first post backwards, thought the KH in the tank was lower than the tap, not higher.

What RTR said.You might have something in your gravel, a decoration maybe, that is raising the KH.

Or it maybe a change in your water supply, spring runoff filling up the reservoirs so that less water is being drawn off wells, some such thing.

In any case, you'll want to keep an eye on your KH. It should stay at least above about 3 dKH (around 60 ppm) in the tank, especially if you're adding CO2, even with a DIY type setup.

Baking soda works. I have perennially softwater and personally like a little crushed coral in a filter bag. Some KH enhancing decor of the type RTR described…