CYA disappeared

[texasmax]

All-

I know there's something about bacteria in soil that can reduce CYA; we used to have drainage issues in the yard and after a heavy rain, we'd have topsoil runoff into the pool and I'd have to add CYA back. Fixed the drainage, and, in general, CYA stays stable, though it usually gets down to the <20 level over winter.

Heating the pool and starting the season early (we're selling our house soon), I added back CYA to get to the 45-50 neighborhood (I use liquid chlorine on a timed feeder), and have been good for a month or so. Woke up to a green pool. Checked my levels, and I'm at absolute zero on CYA (crystal clear with water all the way to the top of the sight test tube). Only thing that happened was a few days of rain (but no soil). We've got a large tree that dumps copious amounts of pollen stuff into the pool. Could that harbor CYA-reducing "stuff"?

Thanks!

 

[mknauss]

CYA reduces primarily due to dilution.

If it has disappeared due to any kind of bacterial reaction, it creates ammonia. Your CC would be high and pH very high. Are they?

 

[texasmax]

CYA reduces primarily due to dilution.

If it has disappeared due to any kind of bacterial reaction, it creates ammonia. Your CC would be high and pH very high. Are they?

That's interesting... FC is 0 from a sample I took and saved from not more than 2 hours ago before shocking. CC was .5 (barely off-clear, 1 drop cleared it up), and pH was ~7.7 (where it's been 7.5 as recent as a week ago). Don't know if those qualify as "high"; I could have very easily been on a downhill slide for at least several days.

 

[Donldson]

What is your FC and CC now?

 

[texasmax]

FC is 0 and CC is .5 pre-shock- you're asking what they are right now post-shock? I dumped in 7lbs of 73% cal-hypo so ~20FC (but it is bright and sunny right now, I just didn't want to wait any longer than I needed to). Will go thru SLAM tonight and hopefully find some liquid chlorine at Home Depot.

 

[mknauss]

If you added chlorine and it is not consumed very quickly, then you do not have ammonia. The CYA reduction is due to dilution or testing variations.

 

[Donldson]

Have you tested your FC and CC since you added the chlorine? That's what I'm asking for.

 

[texasmax]

As of right now, FC is 5, and CC is .5. However, I don't usually measure CC. And I realized I did it wrong (I let the team down!). Correct method is add 5 drops R3, then count drops of 871 (this is on my TF100).
Earlier, I only added one drop of R3, and I got just a bit of pink, the same amount I got after the 5 drops R3 on this last test. And 1 drop 871 cleared it up. So, earlier, my CC was "several times" .5 with lots of rounding error.

So, FC was consumed at a good clip, but, water's green (but not opaque) and a few spots of algae so I'm fighting that, and bright sun.

 

[texasmax]

I slept in a little... after an hour of sunshine, FC=14, CC=.5. Still very cloudy, but white cloudy, from using calhypo (need to get to Home Depot today to check for liquid chlorine). Also need to grab some CYA because I just realized I'm out. Going to get the granular and let it dissolve through a skimmer sock (water is very warm so it won't take long at all).

 

[mknauss]

No reason to bother with the OCLT until the pool is crystal clear.

I thought water in the Dallas area was pretty high in calcium. Be careful how much cal hypo you use.

 

[texasmax]

Hear ya. What ended up happening: last night after sundown, didn't measure and just dumped in enough 10% liquid chlorine to bump me up by 18ppm. Left cya alone at zero for max benefit. An hour after sunrise this morning, still cloudy, 14fc .5cc. Ph7.5 and 100alk (I'm usually 80-90).

Calcium 200-250ish so good there. Then popped in enough granular cya in skimmer socks to get me a little over 30 by this afternoon.