Do I need to shock or not?

[nikon5400]

In ground pool
All parameters are good, with TA about 80, CYA 40-60 (can't figure out the best way to test it)
PH tends to rise to a little over 7.8 and I bring it down every few weeks.
I use liquid 12.5%, about 2 128oz bottles in 4-5 days which keeps FC around 3-5.


It's been too hot lately and I forgot to add chlorine. When I checked I had about 0.5-1 and a few spots with green dust that may be algae (maybe 5 palm size spots on walls in shaded area). The green spots come off right away when brushing or even touching with your hand (dust or algae?).

I remember reading somewhere that you need to shock if your chlorine level got below the minimum according to FC\CYA chart. I tried to find that post, but the new SLAM page mentions a need to shock when chlorine level at 0 and doesn't mention minimum

I added PH down and brushed my walls. Everything looks good. Do I need to shock in this case?

Thanks.

Edit:
CC is 0.5 or lower;
water is clear.

 

[pwrstrk]

I would SLAM it.


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[Butterfly]

Yep, do the Slam process. Maybe the process will be short, if you caught things quickly.

Even tho CC is is .5 and the water is clear, it sounds like you are on the verge of trouble.

You can slam tonight and do the OCLT to confirm.

Welcome to the forum

 

[Richard320]

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[bobodaclown]

When in doubt SHOCK it out!


updated: SLAM it and move on ---http://www.troublefreepool.com/pool-school/shocking_your_pool

Thanks for the update.

 

[Richard320]

When in doubt SHOCK it out!

The proper term is SLAM.

 

[nikon5400]

Thanks guys.

another question -
this site suggests no shocking and keeping chlorine level slightly elevated. can algae get used to higher level of chlorine?

 

[jblizzle]

We do not recommend "elevated" chlorine levels. We recommend the APPROPRIATE chlorine levels based on the CYA level in your pool. Seems that 99+% of people (including people in the pool industry) do not grasp the relationship between the CYA and the FC.

No, the algae will not mutate and become immune to the chlorine.

EDIT: Welcome to TFP, btw!!!

 

[nikon5400]

Right. Labeling on pool chlorine usually suggests keeping CH level 1-3, some up to 5, but never above. And I guess that assumes shocking weekly or as needed, while TFP suggests keeping chlorine level within your specific range all the time.

Another question - if you are at the minimum according to CH\CYA and it starts raining or or just about to... do you suggest adding chlorine anyway... or wait until the rain is over and check level and add chlorine or SLAM if needed? (and once again, add or SLAM if below minimum, but above 0 and no visible algae?)

 

[duraleigh]

wait until the rain is over and check level and add chlorine or SLAM if needed ?

A common "urban legend" that rainfall makes huge differences in your pool water. Unless the runoff runs into your IG pool, it doesn't.

Read this thread and then make adjustments, if any, after it rains.

getting-massive-rainfall-as-i-type-t66271.html

 

[nikon5400]

We had rain most of the day yesterday. Pool was clear before the rain and looked good after with may be a couple very light shades of green or brown which looked more like dust. Right after rain I had FC 2, PH 7.8-7.9. I lowered PH to about 7.5 and then a couple hours later brought up FC to about 5-6 and had pump running for about 2-3 hours

Tonight, about 30 hours later I have about a dozen light green spots which brush off easily. FC is 2.5, CYA is 40
Pump was running for 8 hours (I run it during the day,9-5)

Can FC being below minimum at some point causing this?
Or my CYA testing is not accurate because my agent is a year last year? (leslie's CYA testing is about the same - tested twice, between 30-40.)

I purchased taylor chlorine at leslie's this year and my reading is almost as accurate as last year's 0870 (+- .5 at most)

Thanks.

P.S I use liquid chlorine only

 

[pwrstrk]

You can't let FC fall out of range. 30 hrs is too long without adding chlorine. Your asking for trouble. You can do a OCLT test pool-school/overnight_fc_test to confirm if something is consuming your chlorine. If you fail it SLAM it.

How does your water look.


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[nikon5400]

You can't let FC fall out of range. 30 hrs is too long without adding chlorine. .

I'm sure I had about 5ppm this morning and 2.5 by 7ppm, which means most of the day it was over the minimum.

Water looks great by the way. I just brushed the walls and poured my last two bottles, which should bring CH to about 14. I can smell chlorine though, very little, most ppl probably wouldn't smell it.. but I thought you can smell it only when it fights algae (or may be also when you can smell things most ppl can't? )

 

[pwrstrk]

Yea but you had some green spots. Algae.


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