Since I added the drift woods into my fish tank, after each water change the water turns yellow in 2-3 days, any idea whats the problem is? I know that i have cleaned the drift woods a lot before adding them to my fish tank.

if your driftwood is not weather exposed, meaning all soft parts
should had been decayed due to prolong exposure to weather elements,
it will continuously leach in your tank. it will take time before
it will stop. there is a chance it will develop a white slimy substance
that looks like cotton web around it. only then it will stop leaching
yellow or tan color.

if by yellowish colour you mean it kinda looks like tea then it s the tanins being released from the driftwood. tanins are not harmfull to fish at all and in time will stop commng from the wood and the colour will clear.

the only way to eliminate them is by doing water changes. be patient in time it will clear up.

kool, thanks guys