I have no experience with deni balls. Not sure if the effluent from them is acidic. Test the effluent. If it is acidic, stop running it for the time being.
I would correct the pH issue first, raising salinity back up needs to be done slowly. If done slowly the pH swing will drag out and put more stress on the fish.
Once pH is in normal range then work on your salinity. Try not to increase pH more than 0.1 per day.