I'm finally getting around to completing my Bathroom. I'm installing a 3 piece Lasco show. A friend mentioned to use a lite cement "to set the tub" or bottem of the shower. I think he used the term "Structure lite" he said it was an additive to add to cemement to make it lighter and easier to set. I can't find it at my local stores, Home Depot & Lowe's any suggestions on what can be used and if this is the way to go.