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.
SLAM - Shock Level And Maintain. SLAMing your pool is the best way to eliminate algae, sanitize your pool and get your water crystal clear. If you have algae, or the CC level is above 0.5, or the free chlorine (FC) level is zero, you should SLAM the pool. You cannot do this overnight...it often takes several days to see it completed...no shortcuts.