The best solution for harsh chemicals can be a non-contact level transmitter. These do not come in contact with the chemical and use other methods for measuring the chemical level. Radar level sensors or ultrasonic level sensors are the best choice for harsh chemicals.
However, it must be kept in mind that these level sensors may be prone to other measurement obstacles. Foam and thick vapor can considerably hamper the performance of ultrasonic sensors. In the case of radar sensors, fine-tuning it to avoid these problems can be a cumbersome task. To add to the woes, consider the high price of radar sensors. Besides, the danger of splashing and vapors from harsh chemicals remains, even in the case of these level transmitters.