New to TFP and Just Converted to SWG

[Lobo55]

Looking for advice and comments on the status of my pool and conversion to SWG

24,000 Gal In Ground Plaster, 60 sf PacFab DE SS filter (Orig Filter)
Approx 17 years old, Polaris 3900 (New 2010)
Pentair Challenger Pump (new 2008), Hayward Booster Pump (New 2010)
Auqa Rite T-15 SWG (New 2010)

Issues: High CYA, Black Algae, Quick to Bloom Green Algae, Five foot dia oak tree shades 50% of Pool but also adds lots of organic matter

Test history since test kit came in:
pm pm pm am pm pm
9/8 9/9 9/10 9/12 9/12 9/13
FC 8.2, 15.5, 11.5, 8, 8, 5,
CC 0.2, 0.2, Slight, 0.5, 0, 0,
PH 7.6, 7.8, 7.6, 7.6, 7.6, 7.6,
TA 100, 100, 100, 90, 90, 90,
CH 190, 210, 210, 170, 180, 190,
CYA 200, 200, n/t, 60-70, 50, n/t,

9/8 Major 10" Rain Mud flow in Pool, green brown water, added 5lbs Cal Hypo
9/8-9/10, Filter and Pool Cleaner extra run time, back wash pool clear
9/10 Start SWG process, Drain 40% of water at back wash, add 1.42gal 6% bleech, add 13 40# bags of salt
9/12 am pool 90% full at testing
9/12 pm swg started, 50% run time, Initial salt showing 2,900, add 2 40# bags of salt
9/13 Salt 3000, nothing added

Pool looks best it has in years as of last night (9/13), clear as a bell. Water has stayed balanced through all the changes.

Questions:
1) Should my farthest return have a cloudy look when the SWG is running? More pronounced at start up. Closer returns do not have this visual look.
2) CYA is lower than Auqa Rite suggest. Can I just shock with Di Chlor to raise over time or do I need to buy CYA? After fighting CYA for the nine years we have owned the house, I am viloently apposed to buying the stuff. I have 35 one lb packages left over from my days before TFP.
3) Will CH rise again when I add more salt to get to 3,200-3,400 ppm? If not, should I add CH?
4) TA is close at 90, my thoughts are to just watch and see what happens, agree?

 

[JohnT]

Welcome to TFP.

The cloudiness from the return is a result of the chlorine generation in the cell. Hydrogen gas being given off. Not unusual.

You can use dichlor, but there is no real reason to shock unless you are having problems. If you anticipate needing to shock, you can plan on the dichlor. Or you could just supplement the SWCG with a little daily dichlor dose until your CYA gets where it needs to be. Otherwise add CYA. I understand your reluctance to add more, but it makes life easier on your SWCG and it will last longer. Depending on what you do over the winter, you maybe able to tolerate the lower level until spring since the demand may be lower.

Salt doesn't affect CH. You want to go ahead and move your CH up to at least 250ppm to protect your pool surface.

TA at 90 is probably fine. After you get a handle on how the pH in your pool behaves with the SWCG, you may want to play with TA and adding borates to stabilize things, but you are good for now.

 

[Lobo55]

Update:
Readings from 9/22
FC 4
CC 0
PH 7.7
TA 100
CH 260
CYA 65

FC holding steady at 4ppm for over a week now. CC to zero. I am puzzled by the increase in TA from 90 to 100 with only add to water being 20-25 lbs of calcium chloride. Does calcium chloride increase TA?

I am testing at night due to my schedule so my PH reading last night might not be as accurate as I would like. Will check again but may have to wait until Saturday to get a ph comparison that is accurate. The last time I thought it was 7.8 at night in my kitchen lighting and when I retested the next day in the daylight it was 7.6. Does anyone have any nighttime PH testing tricks?

CYA increasing over time with out any sources being added to the pool (50 on 9/12, 55 on 9/15, 65 on 9/22) is interesting. Do we think this is just settling in after my partial water change on 9/10 and or testing inaccuracy built in to the CYA testing process?

Black algae getting better, but still present. Using Polyquat maintenance dose each week. Should I be using stronger for the black algae or just let the steady chlorine levels and brushing work on it? Will Polyquat clear black algae?

 

[duraleigh]

1. A difference of 10ppm on the TA test is within the margin of error for the test itself - do not worry.

2. There's a pretty big margin of error on the CYA test also. However, anecdotal info seems that others have reported a rise after partial draining and testing much like yours has done. I'm not sure that means anything but I have noticed it more than once. Your CYA of 65 is just fine, incidentally.

Polyquat will probably have little affect on black algae. A better regimen is to brush it daily with a stainless steel brush and elevate you FC levels up to around 8ppm or so and keep it there as long as the black is still visible. It's fine to swim in the pool with 8ppm FC.