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Thread: Getting a noticeable loss of FC over 2 weeks

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    Getting a noticeable loss of FC over 2 weeks

    Hi,

    Recently did a successful SLAM - the scrubbing the sides, tiles with toothbrush , and digging up bits of black algae from the floor , did the trick in about 4 days.

    Always had perfectly clear water , and good balance, but was losing lots of FC.

    Since then, over the last two weeks (except a 3 day period when my pump blew out and so I had to wait for a new one to be installed) , everything has been ticking over fine - all levels good. Even since new pump installed 1 week ago, I have been tweeking and got it stable at 6 hours run time, at 40% on the SWG, holding nicely at FC 7-8.

    Last 2 days , I noticed it not holding, so increased to 50% , then 60% - it was then struggling to hold at FC 6 yesterday - even though it was a cloudy day.

    Last night, I kept pump running and turned SWG up to 80% , this morning at 9.30 am it was at FC 8. SO basically with it running all night, it only gained 2 ppm.

    What does this tell me? Something is eating the FC? Not badly right now, but could be something , right?

    I have turned it to super CL for now, to see if it can fight it off without a SLAM.

    Is it possible , if you catch it early, to increase the SWG and leave it running , to kill off what is eating the FC? OR, is it always going to be a losing battle and I will need to do another SLAM?

    One last thing, the only thing I did not do on last SLAM , was remove the light fitting and clean. As it passed, does it matter, or should I do that as a priority right now ?

    thx
    12k SWG pool, free form. 1HP flotec pump, P90 Leslie's filter. Florida. Taylor 2006 test kit. I think plaster, waiting verification from here.

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    cowboycasey's Avatar
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    Re: Getting a noticeable loss of FC over 2 weeks

    I know you don't want to hear this but if algae has begun your SWG will not have the ability to get rid of the outbreak.. You would need your FC level to be at SLAM level and your SWG just can not get that high.. I think you caught it soon enough that it wont take to long to finish a SLAM.

    It could have been the light still had some greenies left in it and it spread when your FC got to a low point before your pump and SWG turned back on.

    turn your SWG off
    Take your FC up to SLAM level for your CYA level until you pass the OCLT
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    Re: Getting a noticeable loss of FC over 2 weeks

    Just as I suspected lol. Just was not sure if sometimes, if you catch it early , sustaining FC 10 for a few days would kill it off and not get consumed. Interesting how it is holding steady and not losing the fight. Last time I needed to slam , I was losing 14 ppm per day.

    I did actually keep the FC at 10 ppm, with bleach, while pump was off.

    I did not clean behind the light last time, so I will do it today, let kids swim with it at Super CL today, then dump in 3 gallons of bleach tonight and let it work overnight.

    thx
    12k SWG pool, free form. 1HP flotec pump, P90 Leslie's filter. Florida. Taylor 2006 test kit. I think plaster, waiting verification from here.

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    Re: Getting a noticeable loss of FC over 2 weeks

    How important to clean behind light ? I looked around the casing and it looks clean. Old , but clean. Trouble is, I do not know which breaker the light is on and which switch it is as previous owner seems to have done crazy DIYaround the house and not labelled things. Is it likely to be on lighting loop or pump loop? So, can algae actually get inside the light housing and does water flow there to effect FC ? Are they ALL sealed untils running 12V DC - even in 25 year old house ? If so, the it does not matter if I cannot isolate power . Thx

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    DaninFLA's Avatar
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    Re: Getting a noticeable loss of FC over 2 weeks

    Quote Originally Posted by simonoaks View Post
    How important to clean behind light ? I looked around the casing and it looks clean. Old , but clean. Trouble is, I do not know which breaker the light is on and which switch it is as previous owner seems to have done crazy DIYaround the house and not labelled things. Is it likely to be on lighting loop or pump loop? So, can algae actually get inside the light housing and does water flow there to effect FC ? Are they ALL sealed untils running 12V DC - even in 25 year old house ? If so, the it does not matter if I cannot isolate power . Thx
    are you able to turn the light on/off with a switch? ever?

    the light will be on 12V DC (its in water), the transformer should be near your pump, etc. and would most likely be on whichever breaker your pump is. you are not actually removing the bulb anyway, you are just removing the "capsule" that the light is in. when you remove that screw, the hole thing will float to the surface and the capsule will have a bunch of coiled line that is long enough for the light to sit on the deck of the pool. if you have never removed it, I bet you are gonna find some really nasty stuff in there. you cant see behind, you really need to remove it, I bet that's the cause of your FC loss.

    as far as getting electrocuted...well, um you are already swimming in the water with it

    BTW, what size cell are running??
    Dan
    9,000 gallon in-ground Saltwater pool, plaster, cartridge filer, 1.0 hp pump, Hayward T-15 SWCG, TF-100
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    Mod Squad pooldv's Avatar
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    Re: Getting a noticeable loss of FC over 2 weeks

    That light is probably 120v. Off with the switch is ok, but I prefer breaker too. Turn it on and start flipping breakers off. There is high likelihood that there is plenty o funk behind that light. I would remove.it and check. The capsule is sealed. Take a screw out of the top and it will pop out, there is a tab holding in the bottom.
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    Re: Getting a noticeable loss of FC over 2 weeks

    There is a switch in the lounge that overlooks the pool , that has been labelled as pool light. However, the light has never worked, and many of the switches in this house are wired upside down. I could just take off the wall switch and disconnect one of the wires (carefully) that way it doe snot matter which way the switch has been wired in. When I look at the light is is pretty big - the metal casing has about a 10 inch diameter and the lamp inside looks like the size you would get in a standard light fixture in the house. I just cannot trust any of the crazy wiring in this house, as person before me did a lot of things themselves (badly) . There could even be more than one switch for all I know lol. In theory it should be a sealed unit, so I will just take the risk - even if it is live and something goes wrong , the breaker is likely to go before I get killed. Besides, only 120V - in the UK we use 240v - that stings a lot more lol
    12k SWG pool, free form. 1HP flotec pump, P90 Leslie's filter. Florida. Taylor 2006 test kit. I think plaster, waiting verification from here.

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    Re: Getting a noticeable loss of FC over 2 weeks

    I would not be comfortable working on a light without knowing for sure the power is off.
    You could turn off power to the entire house & play it safe.
    16' x 34' vinyl in ground - 16,500 gal.
    Hayward EC-75 DE filter with Hayward 1hp Super Pump
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