1.5 ammonia is too much. Back to water changes to get down to 0.5ppm or lower.
If you really want to get into technicalities, at your pH and a typical aquarium temperature, 1.5ppm ammonia is where you start to get toxic issues. But keep ammonia + nitrite combined no higher than 0.5ppm will steer you clear of issues and avoid things like pH fluctuating giving you issues.
Not sure that boiling water will do anything.
Moss ball. Any plant will help