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Thread: How long until FC comes down after shock/slam?

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    Daisy08's Avatar
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    How long until FC comes down after shock/slam?

    I was curious to know how long FC levels stay at slam/shock level- meaning how long does it take to have the FC come back to normal levels?
    Also, once I passed the OCLT, do I return my SWG back to the levels I had it previously (85%)? In my small little head, I feel like if I turn my SWG back on full force, the FC level will take forever to come down.

    I slammed/shock yesterday and now we are having company today so I am concerned about having a lot of FC in the water (currently 15). 15 is probably a fine FC to swim in but how long until it gets back to the 4-5 it was previously at?

    Every time I do something new to my pool, it creates more questions. Hopefully in another year or two, I will truly understand my pool.

    Thanks
    18x36 IG Vinyl liner Pool. 25,000 gal. Installed June 2015. Salt Water Hayward Aquarite AQR9. DE filter- Hayward DE3620. Hayward Super Pump variable speed. Taylor K2006.

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    Catanzaro's Avatar
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    Re: How long until FC comes down after shock/slam?

    Daisy:

    Please post up a full set of results. It is safe to swim up to shock level based on your CYA. A FC of 15 is not really high unless your CYA levels are at 20 or less, which I assume they are not. You will loose more chlorine at higher levels because daily losses are based on a percentage and not on a ppm per day. This is why at TFP we recommended dosing your pool daily or every other day.

    Once down to the recommended levels based on your CYA, you can turn on the SWG to 85% and keep an eye on your FC levels. It is probably recommended to test every other day to make sure your chlorine levels are holding steady. If after two weeks, your levels are fine, this will give you an idea on what works and what does not work.

    Every time I do something new to my pool, it creates more questions
    Only come here for advice and no where else. Here, we do not recommend any chemicals or "magic potions' to your pool, besides what is necessary. The key is consistent testing and keeping track of your daily, weekly results. Questions are always welcomed!
    14,700 gallons IG Pool Vinyl Liner - Octal Circulation System
    Hayward Pro-Series 350 LB. Sand Filter Model # S270T - 2" Plumping
    Hayward CL2002 Chlorinator - Hayward Super Pump 2 HP Model # k48m2n111
    Hayward AQR9 SWG 25K Salt Cell & TF-100 Test Kit + Speed Stir
    Gulfstream HE125RA - 117K BTU Heat Pump - Date of Build is 11-2013

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    Daisy08's Avatar
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    Re: How long until FC comes down after shock/slam?

    Ok my CYA is at 50 which is where it was prior to shocking/slamming. I haven't really tested for anything else other than FC/CC which is 15. I know I should have gotten to 20...

    My pool was actually good number-wise prior to slamming (FC 6, CC 0, CYA 50, TA 90, PH 7.4, CH 80- Running filter and SWG 10-7 daily) BUT my liner felt slippery. The slippery liner is tough because I cannot tell if something is brewing or I just have really soft water (salt 3200, low hardness, warm water 85+)? I have not one clue and I am making an educated guess on the last statement. So, now that I have said it, does warm salt water with low hardness cause water AND liner to feel slippery? It is so hard to know what is happening when you have good readings in your pool so that is why I figured a SLAM wouldn't hurt, especially since we haven't done so all season yet. <yikes>

    "This is why at TFP we recommended dosing your pool daily or every other day" What does this mean? See, another question!

    Thanks for the help
    18x36 IG Vinyl liner Pool. 25,000 gal. Installed June 2015. Salt Water Hayward Aquarite AQR9. DE filter- Hayward DE3620. Hayward Super Pump variable speed. Taylor K2006.

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    Re: How long until FC comes down after shock/slam?

    Because you have a SWG, you are not manually dosing. What I meant is that if you add daily, you will loose less in chlorine, than adding weekly. Most of TFP members use liquid chlorine for pool maintenance. Does not apply to you, although the daily consumption will be similar.

    Regarding your question on a liner feeling slippery (slippery is different than slimy). The water is against the liner and mine feels slippery as well, but never slimy. I am assuming you are talking about the walls. I do not believe the warm water and low hardness will cause this.

    You should not be overly concerned as your levels are fine and chances are that your water is crystal clear. You may want to increase your CYA levels to 70 and you can keep your recommended levels of FC a bit lower with a SWG system.

    Pool School - Chlorine / CYA Chart
    14,700 gallons IG Pool Vinyl Liner - Octal Circulation System
    Hayward Pro-Series 350 LB. Sand Filter Model # S270T - 2" Plumping
    Hayward CL2002 Chlorinator - Hayward Super Pump 2 HP Model # k48m2n111
    Hayward AQR9 SWG 25K Salt Cell & TF-100 Test Kit + Speed Stir
    Gulfstream HE125RA - 117K BTU Heat Pump - Date of Build is 11-2013

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    Daisy08's Avatar
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    Re: How long until FC comes down after shock/slam?

    Right, right, right... the SWG is doing all the dosing. I forget that people still have to manually add chlorine to their pool.

    It's the bottom of my pool that is slippery. My neighbor who has the exact same pool, installed at the same time, their liner is not slippery on the bottom so that is what caused me to question mine. So when you try to play in the pool, it is hard to get a footing. I do not think it is slimy.. I don't think. Just slippery when trying to get a foothold on the bottom at times (playing tag and such). We have scrubbed, but that feeling comes back. Last year, we did have an outbreak of something bc pool got cloudy and we had to shock/slam and then it cleared up just fine but that slippery feel comes back. I'll get in pool today and see if the slippery feeling is gone due to SLAM. That should be the tell tale sign, no?
    18x36 IG Vinyl liner Pool. 25,000 gal. Installed June 2015. Salt Water Hayward Aquarite AQR9. DE filter- Hayward DE3620. Hayward Super Pump variable speed. Taylor K2006.

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    Catanzaro's Avatar
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    Re: How long until FC comes down after shock/slam?

    Is it the same liner company and same liner? This one I have never heard. Your levels show no real issues. It is hard to get a footing in any pool (outside the shallow end) as the pool base slopes down towards the deep end and the sides (outside the wall) is sloped as well.
    14,700 gallons IG Pool Vinyl Liner - Octal Circulation System
    Hayward Pro-Series 350 LB. Sand Filter Model # S270T - 2" Plumping
    Hayward CL2002 Chlorinator - Hayward Super Pump 2 HP Model # k48m2n111
    Hayward AQR9 SWG 25K Salt Cell & TF-100 Test Kit + Speed Stir
    Gulfstream HE125RA - 117K BTU Heat Pump - Date of Build is 11-2013

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    Daisy08's Avatar
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    Re: How long until FC comes down after shock/slam?

    I just went in, the liner is def less slippery- no slipping, "drier" feeling. I am convinced that when the liner is slippery, regardless of numbers and water clarity, there is probably some sort of something going on. Some things in life are a mystery I guess.....

    Thanks for the help!
    18x36 IG Vinyl liner Pool. 25,000 gal. Installed June 2015. Salt Water Hayward Aquarite AQR9. DE filter- Hayward DE3620. Hayward Super Pump variable speed. Taylor K2006.

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    kcindc's Avatar
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    Re: How long until FC comes down after shock/slam?

    Make sure to brush once a week... very important to keep it clean and less slippery. Algae creates a biofilm (ie slippery) and brushing is needed to expose it so chlorine can kill it.

    Similar to how your mouth feels when you don't brush your teeth, yuck!
    Karen
    33K IG w spa plaster, Pentair 1HP Whisperflo, DE Filter, SWG CircuPool RJ-60, Dolphin Triton Plus, Raypak Dig 336K BTU, TF-100.
    Pool Math Chlorine / CYA Chart SLAM - Shock Level And Maintain
    2017 replaster/retile

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    Re: How long until FC comes down after shock/slam?

    Daisy:

    A couple of things come to mind:

    1) Brushing your pool regularly is important. At least weekly. This will break up anything on the liner. When I vacuum the floor, this takes care of the bottom. The walls are done with a brush (as needed). Although, I rarely brush because of the circulation system that I have (8 return jets and 3-4 rotating heads) and this really makes a difference.

    2) Weak spots because of return jets and circulation system. How many return jets does your pool have and how are they positioned? How many skimmers and main drains? My pool has 2 skimmers, 2 main drains and 8 return jets. The water moves so fast I can barely see what I am vacuuming through the skimmer and go at it blindly. I just ordered a battery powdered vacuum as a secondary way of cleaning the pool.

    This could have been the culprit of your problem and like you said, some things is life are just "mysterious".
    14,700 gallons IG Pool Vinyl Liner - Octal Circulation System
    Hayward Pro-Series 350 LB. Sand Filter Model # S270T - 2" Plumping
    Hayward CL2002 Chlorinator - Hayward Super Pump 2 HP Model # k48m2n111
    Hayward AQR9 SWG 25K Salt Cell & TF-100 Test Kit + Speed Stir
    Gulfstream HE125RA - 117K BTU Heat Pump - Date of Build is 11-2013

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    Re: How long until FC comes down after shock/slam?

    Daisey, I just finished a slam, and left my SWG unplugged while FC floated back down. Took a few days to get back in 'normal/target' range, then I hooked up SWG again to 'maintain' good FC levels

    Hope that helps on that side of your questions
    Phil
    ~9600 gal gunite pool, NEW July 2015; Pentair Intelliflo 2 VST pump; Pentair C&C 150 filter; Pentair Intelliclor IC40 swg; solar heat w/ Pentair Solartouch controller, screened. Taylor K 2005 test kit, FAS-DPD separate test, Taylor K1766 salt test

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    Daisy08's Avatar
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    Re: How long until FC comes down after shock/slam?

    Yes it does help! That to me makes the most sense- turn off the SWG. My husband is too afraid to let me totally turn off SWG so I have it down to 50% so ours will probably take a little longer to come back down. But now I know it will take a few days to maybe even a week.
    18x36 IG Vinyl liner Pool. 25,000 gal. Installed June 2015. Salt Water Hayward Aquarite AQR9. DE filter- Hayward DE3620. Hayward Super Pump variable speed. Taylor K2006.

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    Daisy08's Avatar
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    Re: How long until FC comes down after shock/slam?

    Wow you have a lot of jets. We have 1 in shallow and 1 in deep- angled right. My husband had them tilted up such that it was creating bubbles on top of water (because he likes the bubbles) but I made him angle them lower... you can still see the flow of water though. I could see how having more jets would help with circulation bc we def.have dead spots.

    I agree, we should be brushing more. We sort of waited to start brushing until the pool felt slippery and probably by that time, it was too late. Just need to do it regularly I guess.

    Thanks for the help!
    18x36 IG Vinyl liner Pool. 25,000 gal. Installed June 2015. Salt Water Hayward Aquarite AQR9. DE filter- Hayward DE3620. Hayward Super Pump variable speed. Taylor K2006.

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