Moved into a house with a pool built in 2006. House was built in 2002. Quick overview: when I took ownership the pool had a lot of debris at the bottom, pool floor covered in algae and dirt. Purchased manual vacuum and other pool cleaning supplies and cleaned it up a bunch. When the pump turned on it was blowing large bubbles from two return jets for 30-60 seconds then operated normally. Figured this was a water level issue so filled up to half way mark of skimmer and everything seems to be okay now.
With the help of a family member, cartridges were cleaned. HTH Chlorine Tablets have been used and continued to be used under my ownership. Have not taken readings but do have a test kit and will arrange for that today.
Pool specs: Approx.: 11000 gallons +/-. Deep End: 5 ft. Length: Approx. 27 ft. Width: Approx. 11 ft. 2 main drains, 1 skimmer, 1 vacuum port. 3 return jets.
Pool pic and pump pic: