I recently changed my 75 adding Driftwood and all is well about 3 months post the change...I have debt with (2) issues thus far...
1. The wood wouldn't sink, I actually drilled small holes in the wood and used fishing line to tie it to the underground filter...3 months later it is still holding up and I would imagine that it would sink on its own by now.
2. The other issue is that the water turned yellowish due to the wood, so with regular water changes, it is now clear and my understanding is that this is a common occurance.
I have have almost all cichlids and the PH hasn't been an issue at all.
YOU BE THE JUDGE is the thread I posted and it is on this forum a page or two back. Pictures of both my old and new setup are there as well.
Good Luck,