Home Depot might be able to answer your questions, but if you are leery of taking their advice on something as important as this, you might want to contact the manufacturer of Envirotex Lite, which is Environmental Technology Inc. Here is a link to their 'Envirotex Lite' webpage: http://www.eti-usa.com/consum/envtex/envlite.htm
Here is a link to their contact page. Besides snail mail or a possibly long distance phone call, you can type them an online email if you want. http://www.eti-usa.com/contact/contact.htm