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.
First, brush off the head of the Black Algae, then broadcast the Algi-ban over the Black Algae and let it sit for 24-48 with the pool off. Remember not to let it pile up in one area of the pool or this will leave a discoloration burn mark much like one left by dropping a 3 tablet into the pool.