Have mustard algea for a few months now. Not all over the pool, just along a south facing wall, intermittent. I have been adding about 1-2 quarts of acid per week. Took water in to pool store and helpful guy tested right in front of me:

FAC - 2.0 ppm
CAC - 0 ppm
ph - 8 +
TA - 120
CYA - 50 ppm
Salt - 2700
Said calcium hardness wasn't necessary

I have in ground, 22,500 gallon pool with 7 ft round spa, pool pilot SWG, solar, plaster. I have the SWG up to level 3 (highest level) at about 50%. The cell is rated up to 48,000 gallons, so my pool is on the very bottom end of size for the cell. I always wondered why the cell was cranked up so high in relation to my size pool. Also, I was told to take the sample close to one of the returns.

My SWG reads 3100 on salt reading - should I re-calibrate or wait until everything algae issue resolved and pool balanced.

Here's what the pool guy said:

1. Ph is high, so that driving the chlorine down.
2. Once Ph gets taken care of, chlorine will level out (with FC of 2...seems like chlorine is fine to me).
3. Stabilizer is kind of low (pool pilot recommends 60-80, pool store recommends 30-50), but didn't want me to add any...see if pool can balanced w/out adding first
4. Alkalinity is high, would like to see lowered to 90 or so (pool pilot recommends 80-150, pool store recommends 80-120)
5. To lower alk 10 ppm, i need to add 48 ounces of acid.

Here's what he recommended:

1. shut pump off, add 1 gallon of acid to a few gallons of water. add to deep end
2. wait 15 minutes
3. while waiting, brush all plaster
4. turn on pump, let cycle once (4 hours for me)
5. force solar valve on (if too cold to have it done by temp)
6. add 16 ozs of yellowtrine to pool
7. add 1 bag of chlorine shock to skimmer to run through solar
8. add 1 bag of chlorine shock to pool
9. run for 24 hours.

Any thoughts? Is this bogus, or am I heading the right direction? A 3 lb container of the yellowtrine was $20...am I just getting ripped off, or is this reasonable (I'd even settle for expensive, but worth it). Any problem adding chlorine shock to salt pool (I have non-chlorine shock, but he said to use the chlorine stuff instead)?

Thank You!