Hey guys and girls. My tank is now almost 4 weeks old. Nitrite is perfect, Nitrate is perfect, Ammonia is perfect but my pH is yellow (around 6??) It was bang on 7.0 when I started the tank and the only changes I have made are adding a big piece of bog wood and plants two weeks ago. I have a silver shark, angel, two black widows and a barb in there atm (260L). Is it the wood or plants causing the pH to drop? Any recommendations to get it back to 7.0?