Beware of using the salt without input from an experienced Clown Loach keeper, I only added salt to mine in small amounts after a visit from two experienced fishkeepers who were buying fish from another tank of mine.
I suspect you want more heat then 25/26C, my Juwel heaters often "underheat" like your one appears to be doing when set at 30C. Unless you had good reason not too (like I did with riverine fish that normally live in sub-tropical water that is oxygen rich), aiming for a true temp of 30C will speed up the Ich cycle and get them to the free swimming form quicker (the only phase where the meds can kill the protozoa). I ended up settling at 27/28C, because my synos were showing obvious stressing at the temp increase by trying to swim at the water surface in the line of fire of the external filter.
Makes me wonder if your Ich problem, which Clown Loaches are prone to, is due to you thinking your heater was really heating to at least 24C when it was actually lower?