I've been thinking about adding a couple pieces of Driftwood to my aquarium, but i don't want my ph to decrease. I have polished river rocks as substrate in my tank and don't want to switch to crushed coral to keep a high ph. i already have a little bag of Crushed coral in my wet and dry sump, but if i add Driftwood to my tank... will it still lower my ph?? If so... how much lower will the Driftwood affect my PH?