The most common cause of a goiter is lack of iodine, ...Even with the right amount of iodine, the thyroid gland can swell, creating a goiter. This can occur in any type of thyroid disease, including hyperthyroidism, hypothyroidism, thyroiditis, and thyroid cancer.
Shock treatment powder bags. Skim off whatever algae you can from the pool using a pool skimmer. Scrub the inside edges and walls of the pool with an algae brush to dislodge stuck algae. Purchase sufficient amounts of algaecide, as noted in the instructions on the bag, that match the total gallons of water in the pool.
Brush the algae off your pool walls and floor using a pool brush. Also, brush the entire pool. You want to break up the algae and get it in suspension so that the chlorine from the shock can attack and destroy it.