Large Snake Plant #freecycle

Months ago I bought this snake plant at ShopRite (big mistake to buy there) and it had fungus knats. I have changed the soil twice yet the knats return. I have also placed a 1/4” of non-salted sand on top of the succulent soil. I give up and am ready to trash it unless somebody has the patience to de-knat them. Despite the knats, the plants look healthy and have grown twice their size since I got them. Height around 3ft. Weight is about 20lbs, keep in mind if you’re going to carry a long distance.