Is it time for me to Shock my pool? *OCLT #3 Complete PASS!!!

May 16, 2015
31
Columbia, SC
You'll have to excuse my ignorance and what I am sure are questions that have been answered. This is my first year with the pool and my first experience with algae. A few weeks ago I started noticing green algae blooms in the shaded portion of my pool. I maintained the pool throughout the winter, as to not let my levels get too far out of whack. However, the FC drifted a bit and when the algae started showing up I got them all back in check. I thought the algae problem might resolve itself with corrected levels and frequent brushing. Unfortunately that plan hasn't worked and every few days a small amount of algae will pop back up.

The pool looks fine otherwise and the water is clear. Before I dump 8 gallons of bleach into my pool I'd like to ask, is shocking the pool my only recourse at this point? I feel like I know what the answer will be. So I have a few follow up questions. Once shocked how long should I keep people out of the pool? Should I be turning off my SWG during this process?

FWIW, These are my current levels:

FC 6.2
PH 7.5
TA 80
CH 160
CYA 80

Thanks for the feedback and the help!
 
Re: Is it time for me to Shock my pool?

Hi Chris, and welcome to TFP! :wave: No silly questions here. When it comes to algae, chlorination is your best friend. Not just any chlorination, but regular liquid bleach because it's pure in sodium hypochlorite and leaves next to no residual by-products. You'll receive a ton of great info simply by reviewing the links below in my sig. But for now, you need to "SLAM" also below. We don't do short-term shocks that most people think of. We maintain the proper elevated FC based on your CYA to achieve maximum results.

In your case (CYA of 80) your SLAM FC level is 31. It will eliminate the algae when all items on the SLAM page are completed properly. Hopefully you have a TF-100 or Taylor K-2006 to test FC at that higher level. If not, let us know and we'll let you know your options. Let us know if you have any more questions.
 
Re: Is it time for me to Shock my pool?

A sustained shock will kill that algae for keeps. Hence our SLAM acronym Shock Level And Maintain.

Check behind lights and beneath ladder rungs and steps. Those are good hiding places for algae to hide out and regroup.

Conventional wisdom has you turn off the SWG during the process. If you're not there to monitor it, you could go too high on FC and start bleaching the vinyl liner. It also has to be off to run the overnight loss test at the end. That being said, I myself would be likely to leave the thing on, at least at its normal setting while I was at work. It's a gamble I'm willing to take. You may has a better sense of aesthetics than me and not want to risk the liner.
 
Re: Is it time for me to Shock my pool?

Yes I do have a Taylor K2006 kit. I've got more R0871 coming tomorrow so that I can keep up with the test demands.

I've held off on doing the Shock until today due to some heavy rains. The algae got much worse after the rain as well. I didn't want to throw money away on chemicals. I started with a FC reading of 3 and added 10 jugs of 8.25% Bleach to hit my target of 31 (CYA 80). I've got the pool running 24 hrs a day now and will check my FC level tonight, is that too soon?

I'll try to post my progress here as I go along. Hopefully others can learn along with me.

Thanks for all of the help.
 
Re: Is it time for me to Shock my pool?

You need to be checking your FC and CC, every couple of hours during the beginning stages. Once the FC level starts to hold, then you can stretch it out a bit.

The routine is; Test, use pool math, add chlorine as indicated, wait a hour or so, repeat.
 
Re: Is it time for me to Shock my pool?

I just checked my FC level and I'm sitting at 30 ppm. The algae is pretty much non existent at this point. Additional brushing didn't seem to stir up any algae like before. The water is a bit cloudy now. I'll retest in the morning and proceed from there.

image.jpg
 
Re: Is it time for me to Shock my pool?

Quick update. I ran out of R0871 during my test at noon but I could tell the chlorine was low so I turned on the chlorinator while I was at work. Came home, got my R0871 refill and retested. Chlorine level read 23 ppm. 3 more bottles of 8.25% in shortly after and turned the chlorinator off. The pool looks really good. I think I'll try the chlorine loss test tonight.
 
Re: Is it time for me to Shock my pool?

Thanks for the link. I've probably read that a dozen times and will probably read it another dozen in the next few days.

Test for FC at 8:15 and got a reading of 29.5 ppm. I thought it would be higher after adding 3 gallons of 8.25%. I imagine the sun killed off some of that. Anyhow, I added another gallon and will test again here soon.
 
Re: Is it time for me to Shock my pool?

OCLT complete. I tested the pool almost an hour after the last addition 121 oz of bleach and read 34 ppm FC at 9:15 PM. Tested this morning at 5:45 AM and read 31.5 ppm.

I know this doesn't meet the <1 ppm overnight loss, but I'm wondering if the 2.5 ppm loss is due to additional dilution/distribution of the bleach added last night or me busting the 31 ppm FC target for my CYA reading (80 ppm). The water is clear and looks really good. Should I continue to stay the course with the shock or can I call this 'good' and let the FC levels recede back to normal?

If the answer is to continue to shock, is it acceptable to bring the pool up to shock levels late in the evening? My work location and schedule makes it difficult to maintain the 31 ppm target throughout the day.
 

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Re: Is it time for me to Shock my pool? *OCLT Complete

I would recommend this .... keep it up at SLAM level even though you have to leave. When you get back, take it up to SLAM again (31 right?) but don't go ANY higher. Once I was in your EXACT same shoes. Same CYA/FC - everything. I exceeded the FC thinking no big deal. But at that high level, going over the FC was too much and I lost exceeds. I went through 2 bottles of drops. :brickwall: The first time I ensured my FC was at 31, I passed.

So keep doing what you're doing, and try it again tonight, just don't exceed the FC SLAM. See if that works better for you. :)
 
Re: Is it time for me to Shock my pool? *OCLT Complete

What was your CC?

CC was almost non existent. The change from 1 drop was barely noticeable. I'd say it is less than 0.5 ppm

I would recommend this .... keep it up at SLAM level even though you have to leave. When you get back, take it up to SLAM again (31 right?) but don't go ANY higher. Once I was in your EXACT same shoes. Same CYA/FC - everything. I exceeded the FC thinking no big deal. But at that high level, going over the FC was too much and I lost exceeds. I went through 2 bottles of drops. :brickwall: The first time I ensured my FC was at 31, I passed.

So keep doing what you're doing, and try it again tonight, just don't exceed the FC SLAM. See if that works better for you. :)

Perfect. I'll give it another go today. It wasn't my intention to bust the FC target so badly. The gallon of bleach should have taken me from 29.5 to 32.5 ppm. I'm not sure how I messed that up. I'll see if I can get it nailed tonight.
 
Re: Is it time for me to Shock my pool? *OCLT Complete

OCLT #2 is underway. We had a cool cloudy day and the chlorine loss wasn't that great. I got lucky by turning on the chlorinator for a few hours. I did two tests and measured 30 and 31 ppm FC with no CC that I could tell. Hopefully tomorrow mornings FC tests will be similar. The pool is looking great.

IMG_1518.jpg
 
Re: Is it time for me to Shock my pool? *OCLT #2 Complete FAIL

Ugggghhhh. OCLT #2 under my belt and that did not go as expected. I tested about 20 minutes ago and got a result of 21.5 ppm. That's disappointing as I thought I'd be in the clear.

Two things that I think may have impacted this test; my testing technique and dropping the Dolphin in the pool. Admittedly, I've been lazy with the FC test. I did some reading about test variability last night and I think I'm causing issues by not swirling during the R0871 addition, I really wish I had a SpeedStir. Typically, I add about 50 drops, swirl then start the swirl/drop technique until the fluid turns clear. I think this may be causing some error. This morning I was very careful to swirl while adding drops and got the 43 drops.

On to test #3!
 
Re: Is it time for me to Shock my pool? *OCLT #2 Complete FAIL

I love me some speedstir, it does make it easy.... You really need to swirl while dropping and it can make a difference if not done...

YOu will get there, you still killing some greenie's :)
 
Re: Is it time for me to Shock my pool? *OCLT #2 Complete FAIL

YESSS!! OCLT #3 is a Pass. Nailed the 31 ppm target last night and measured 30 ppm FC, <0.5 ppm CC this morning. I went ahead and order a SpeedStir in the event I have to go through this again. I added a total of 17 bottles of 121 oz 8.25% bleach. The TFP method worked as promised. Thanks for everyone's help and support.
 

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