How To Increase Kh

[marty2905]

I have set up a Malawi Cichlid tank a few weeks ago and I am using Seachem's Malawi Victoria Buffer and Cichlid Lake salt. The problem is my KH is only 90ppm but my GH is 160ppm. I have some crushed coral sand mixed in the substrate and some Texas Holy rock to increase the KH but its still too low. Can I add more Malawi Victoria Buffer to increase the KH? my pH is about 8. The problem where I live the water is very soft, when I test tap water the kH is so low that one drop of indicator sends it yellow.

 

[Blondielovesfish]

Crushed coral is one way that I've heard, though I've never tried it myself.

 

[crisycrunch]

Use some Kalkwasser.  Used in saltwater tanks to raise ph, alkalinity and calcium.  Usually not too expensive and make sure you add it slowly to the tank.

 

[Lateral Line]

It's ironic isn't it. People with hard water want to soften it, and people with soft want to harden! I envy your location!

 

[TwoTankAmin]

Crushed coral or coral sand are not instant. They take time. KH comes mostly from carbonates. because you are doing rift lake fish you can add some sodium bicarbonate to raise the KH and this will also move the pH towards 8.2.
 

 
To raise the KH without raising the GH, add sodium bicarbonate (NaHCO3), commonly known as baking soda. 1/2 teaspoon per 100 Liters raises the KH by about 1 dH. Sodium bicarbonate drives the pH towards an equilibrium value of 8.2.

from http/fins.actwin.com/aquariafaq.html
 
You may want to consider finding a good recipe for DIY rift lake mixes as opposed ti the pricier SeaChem stuff.