CYA or Chlorine First?

[phlach]

Hi All,

In ground pool, ~20k gal, closed last year (was sick, long story). Opened about a week ago to a green swamp. CYA measuring zero.

Have twice added about 10lbs of cya (20lbs total) slowly via skimmer, but understand now after some reading that I may have backwashed much of that out from my sand filter.

CYA still measuring zero. Added large sock full of cya to skimmer basket last night, and this morning it's completely empty.

Meanwhile, have of course been adding tons of bleach. TC is up around 30 but FC I'm having trouble keeping above 2. Pool is no longer green, even when I vacuum or sweep, just a milky white with only about 12" of visibility.

So, clearly I need to get that FC up, but I'm wondering about the CYA and if I should even worry about CYA until I get the pool back in shape. Could all the CYA I've been adding just be "feeding" the contaminants? Should I keep trying to get CYA up WHILE I'm shocking the pool? Or is that just aggravating the problem?

Thanks!

 

[Smykowski]

With your CYA at 0 and your TC so high, it sounds like you have an ammonia issue. We've seen a lot this spring, search for "ammonia" and you'll have plenty of other experiences to see. For now, keep adding bleach until you can get somthig resembling an FC reading of 10, then you can add the CYA and start the SLAM properly.

Can you post a full set of test results?

 

[phlach]

Thanks, I'll read up on ammonia as I don't think I've ever had to deal with that before. I miscalculated earlier. My TC this morning was around 15, not 30. With a few hours of sun, as you can see blow, that plummeted despise adding a couple gallons of shock this AM.

Just took a full set of readings.

CYA: Unreadable (0)
PH: 7.4
TC: 2
FC: 1
TA: 120
Calcium Hardness (which I haven't typically tested for) is 40.
Appearance: Still white cloudy with about 12" visibility.

Clearly I need to go add lots of bleach to get my FC up. Any other recommendations? During the day with bright sun, should I still be trying to keep FC near 10 (seems almost impossible) or just overnight?

 

[Richard320]

With the right conditions, all the CYA you had last year turned to ammonia this year. It takes a LOT of bleach to eliminate the ammonia. It will react and consume the bleach almost as fast as you can pour it. So much bleach you start to question your sanity and your test kit.

Once you eliminate all the ammonia, it should hold better. Then worry about raising CYA. But keep taking it to SLAM.