Wulfonce, I've used salt for both loaches and catfishes with no issues. I indicated this in my ich article, a compilation of several accounts of experience from several MFK members that salt should not harm your loaches if properly administered. The most important step is dissolution. Many people forget that the salt must be dissolved to avoid the grains from burning the skin of your fish which otherwise, adds unnecessary stress to the fish.
Maintain the temperature to 86 degrees Fahrenheit. Add a teaspoon per gallon of salt. Be sure to dissolve first before adding. Add the second set after 12 hours. A total of two teaspoons per gallon of salt will be adequate enough to destroy the protozoans. Continue the treatment process for 10 days at least. Be sure you aerate the water properly as both high temperature and salt will significantly diminish the oxygen supply.
Lastly, regarding the kind of salt to use, any sodium chloride will do. Just make sure you are NOT using one that contains yellow prussiate. Iodine is not an issue so you're just fine using iodized table salt.