What Makes And Affects Your Kh?

[Incitic]

Just wondering because Ive got two tanks that get their water from the same place, have driftwood and live plants yet one of them has a KH degree of 2 and the other 4.

 

[George Farmer]

The carbonate hardness in your tap water generally "makes" the KH. It can also be boosted by calcium-rich substrates i.e. pea gravel or decor (some rocks or stones).

KH can be reduced by acidifying in the water i.e. excess biological loading, decompsoing matter in the substrate etc. Some woods will also have the same effect. Peat filtration the same.

One other factor is that some plant species will extract bi-carbonates from the water as source of carbon. Vallisneria sp. and Egeria sp. are two I know of. However unless growth is rampant and the water isn't changed regularly then I doubt this will cause a drop in KH.

 

[George Farmer]

The carbonate hardness in your tap water generally "makes" the KH. It can also be boosted by calcium-rich substrates i.e. pea gravel or decor (some rocks or stones).

KH can be reduced by acidifying in the water i.e. excess biological loading, decompsoing matter in the substrate etc. Some woods will also have the same effect. Peat filtration the same.

One other factor is that some plant species will extract bi-carbonates from the water as source of carbon. Vallisneria sp. and Egeria sp. are two I know of. However unless growth is rampant and the water isn't changed regularly then I doubt this will cause a drop in KH.