Give us more info on tank size, lighting etc. so we can help furthur.
Your "brown fuzz" sounds like beard algae, this has many causes but will be due to an inbalance somewhere i.e. too much lighting, high nitrates/phosphates, too much liquid fertiliser, not enough plant growth etc. Siamese Algae Eaters will have a limited effect but you're better getting to the cause of the algae than treating the symptom.
If your sand plain then your Swords are unlikely to be getting enough nutrients through their roots, root tabs will help. Long-term though sand will compact and cause all sorts of problems unless it's regularly maintained.
HTH
