I got my pool out of balance and had an algae problem. Basically a heavy bather load was not properly taken into account. The FC was raised to 30 ppm with HTH, the CYA was around 70, Alkalinity was low due to rain corrected with sodium bicarbonate to 100 ppm. Calcium level is 260 ppm
Got a huge milky water problem that yielded a white back wash flow. I am guessing that this is the dead algae
The cloudiness would not filter quickly. Opened the filter a TR 140 Pentair and found a lot of hairy scum in the sand around the sides, clearer towards the middle. Filter in service for about 5 years, backwashed only.
I am removing the good sand and washing it and reusing, in addition using 200 lbs of new sand for final fill in top of filter.
Sand in Honduras where we are located is close to $20 per bag as it is all imported. (900 lbs needed for full refill)
When refilling with water before backwashing, will add filter cleaner and allow to sit for a day.
I have a 45 foot negative edge on this pool and no skimmer so don't have a way to add the filter cleaner during a back wash.
Question, Is it better to use pebbles beneath the laterals?
Any ideas on procedure would be appreciated.