Hi all, lurker for 3 years. Business kept me busy 14+hr days, 7 days a week for most of this year so I had unintentionally neglected consistent pool maintenance. With new hires balancing my load, I now have time to commit pool maintenance to completion.
Pool had been decently swamp free for most of the year until the last few months:
[1st algae bloom in May] Due to low water evaporating below skimmer causing circulation to not run during a weeklong business trip away, corrected with SLAM. Lowered TA to approximately 100 (Hindsight, should have known to lower to 60). CYA was 40 (Hindsight, should have raised it to 70 but with preference of leaving CYA low due to previous horrors of 200+ CYA (pool company are ding dong people) until 3/2015 and draining/refill became an engineering challenge because of high water table). Water perfectly clear though I cranked SWG up 75% to maintain FC preference of 3.
[2nd algae bloom into swamp started middle of July] Compounded with never before had issues:
- Issue with SWG flow sensor not allowing cell to run even though had enough flow (fixed)
- not realizing CYA drifted <30 due to excessive rains causing significant overflow (should have tested more often and realized because salt demand was +800ppm in the course of a month)
- pressure cleaner decided to give up for the 6th time again (finally pulled trigger with Triton Plus robot)
- Excessive scaling to the cell due to having it run extended periods 75-80% duty cycle with pump 24hr/7days (hottest summer here in FL on record) and didn't correct pH below 8.0 consistently enough (see 1st algae bloom above for why +8.0pH occurred more often).
7/23/16 brought CYA to 40, pH to 7.4, then started SLAM...took 6 days before all 3 parameters passed with OCLT passing 3 times in a row of 0ppm loss overnight 7/29,7/30,7/31 all at 18-20FC for good measure because I was cleaning the filter, running the waterfall, or extra scrubbing of skimmers/walls).
Once SLAM was completed, I noticed that I have serious metal staining (brown, rust colored maybe Iron?) that was not present after 1st SLAM of this year. It is pretty bad, covering multiple parts in the bottom of deep end of the pool and slight precipitation in the bottom shallow end where the algae and/or sand sat for a little while before vacuuming during SLAM. No staining on side walls. Trichlor puck takes an hour to do a little improvement, vitamin C tablet seems to be a little faster but I can't tell. Am I right on metal staining? Is my city water the cause of the problems? Or need to do more testing before jumping into ascorbic acid?
So now I want to correct 3 major issues:
1. Remove stains
2. Decrease SWG duty cycle
3. Decrease acid demand
Current test (as of 8pm 7/31/16) Taylor K-2006:
FC 8.5 (I have 8hr of direct sunlight so I expected to lose over half of FC, was 18.5FC at 7am...FC loss was approximately the same during the day after OCLT verify pass in the mornings)
Please verify if my methodology makes sense. I am supposed to have a pool party at the end of the week. Stains won't scare anyone, I think.
Step 1) Between now and pool party, add CYA to 70-80 using granules, wait for FC to drop to 3 then turn on SWG and adjust to aim for 3-4FC, and keep pH at 7.5 by adding muriatic acid repeatedly [stain stays, SWG duty cycle will hopefully decrease, acid demand may decrease]
Step 2) After pool party, turn off SWG, let the FC go down close to 0, perform ascorbic acid treatment (I am assuming I am right, see above), put sequestering agent, put polyquat 60. [stain removed]
Step 3) Use baking soda to bring pH back up to 7.2. Get back to normal, 3-4, FC levels using bleach...
Step 4) Once FC and pH is in range, turn SWG back on and tackle TA by bringing down to 60 using muriatic acid/aeration. [all major issues fixed]
- Most importantly, is my method correct or flawed?
- I don't use borax so should I start using it in step 3 instead of baking soda to take advantage of AA treatment possibly reducing TA?
- Will CYA be affected after AA treatment and addition of borax? If so, would it be wise to correct CYA later at step 4?
- Should I correct TA at step 1 to prevent precipitation of metals by aeration accidentally raising pH above 7.2?
- Should I consider waiting until the weather gets cooler to perform AA treatment and reduce risk of algae occurrence?
- Can I put polyquat 60 before AA treatment?