I had a 7.8 PH going consistently in my tank for a few weeks, but the last few days the PH has dropped down to 6.6. I think it dropped when I introduced the aquarium salt. I thought about using PH up to get my PH back up in the 7s. Wouldn't that be recommended for my setup? What PH do you recommend then if no? What should I use to get my PH to rise to a different level?