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Thread: Dropping CYA by Overflowing?

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    hellstorm2004's Avatar
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    Dropping CYA by Overflowing?

    Hello Everyone,

    I am trying to drop my CYA. I am trying to overflow the bad water by adding fresh water and letting it overflow? Is this a very good idea though.

    Although i am seeing results but just taking too long. So much wastage of water is something i do not like. My starting was 100, after a about 10 hours of overflowing it has dropped to 70. I want to get it down to around 30/35.
    Purex Titron FNS DE Filter 25000 gallons approx.
    Century A.O. Smith B855 56Y 2HP Motor. 40x25 (approx). Plaster surface.
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    Divin Dave's Avatar
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    Re: Dropping CYA by Overflowing?

    The prob with this way is that inevitably, some of the fresh water will go out with the bad. It will work as you are noticing, but it isnt the most efficient way to do it.

    Is there some reason why you cant to a partial drain and then refill?
    Divin Dave,
    IG Vinyl, 15' x 30', 3 1/2' - 6' deep, Oval, ~15K gal, Intelliclor IC40, Intelliflo VS pump, Clean and Clear 420 Filter, auto-fill-disabled, Retrofit LED Color Light, Dolphin Nautilus Robot, TF100 Test Kit, Taylor K1766 Salt Test Kit, Tftestkit Pressure Gauge.
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    Texas Splash's Avatar
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    Re: Dropping CYA by Overflowing?

    I'll give you my opinion .... .... if you're at 70 now, just eave tt there. It's blazin' hot here in TX. Protect your FC. My CYA is at 60-70, and I know others who are as well. As long as you keep your FC at the target and never let it drop below the 5-6 mark, you should be okay. It will probably deteriorate a bit on its over the winter as well.

    If you're really firm on lowering, then yes, doing it the way you've been is a bit slower and less predictable, but it's better than nothing.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
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    hellstorm2004's Avatar
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    Re: Dropping CYA by Overflowing?

    What i did was let the fresh water in from the bottom of the pool. That being cold water should be at the bottom. Although this being a pool not an ocean, i agree that fresh water should leak out. About dumping the water out, i am just being lazy i guess and managing a house single handed is just becoming overwhelming!

    Thought i would try it, if it did not work, i would go for dumping the water out.

    I know its hot here, the thing is when it was about 100, it was eating 13-14 liters of bleach in about 7-8 days.

    On a different note, how many liters of bleach do you normally need in a month?
    Purex Titron FNS DE Filter 25000 gallons approx.
    Century A.O. Smith B855 56Y 2HP Motor. 40x25 (approx). Plaster surface.
    TFT-100 Test Kit.
    Rainbow Lifeguard 320.
    DX5+S Cleaner.

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    Mod Squad woodyp's Avatar
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    Re: Dropping CYA by Overflowing?

    I don't think your high CYA level was causing your pool to "eat" that much. My pool is half your size and I add 80 ounces daily in full sun for a daily loss of 4ppm.
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    Texas Splash's Avatar
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    Re: Dropping CYA by Overflowing?

    Yeah, in comparison, my pool is at just under 18K, and I use about 4 - 4.5 ppm depending upon my current CYA. Depending upon the intensity of the sun, I'll use 3/4 - 1 gallon which is why I've been increasing my CYA to 60 and slight even higher than that after completing an OCLT to ensure there was no bad stuff in my water eating the FC. It's a balancing act.

    - - - Updated - - -

    By the way, every time I see your avatar it reminds me of the movie Eurotrip.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
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    Re: Dropping CYA by Overflowing?

    Mine?
    Well its the only sports team i really care about!!

    Does dirt/debris eat chlorine up? Like added about 3.8 gallons of bleach around 08/22, to make FC of 12 from the CYA chart. I checked on Sunday and its was 4. That's about 8 days. Now it probably has gone to 0 FC with all the fresh water being added. I will test the water today and see where the CYA is at and add fresh bleach again.

    If i take the whole of August gone through about 11 gallons.
    Purex Titron FNS DE Filter 25000 gallons approx.
    Century A.O. Smith B855 56Y 2HP Motor. 40x25 (approx). Plaster surface.
    TFT-100 Test Kit.
    Rainbow Lifeguard 320.
    DX5+S Cleaner.

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    Texas Splash's Avatar
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    Re: Dropping CYA by Overflowing?

    31 days divided by 11 gallons is about 2.8 gallons per day. That would seem excessive. Dirt and debris certainly can increase FC consumption. Try to stay in a good routine. You definitely don't want it dropping below your FC target, not to mention zero, or you'll leave yourself open for algae in this blistering heat.

    Best thing to do is record your FC loss each day, or even do an overnight test. When performing the OLCT, remember that it must be done when the sun has dropped – no sunlight on the pool. About 8 hours total is recommended. Also, your FC level should be elevated more than normal. Starting (bedtime) FC could be close to your SLAM level, but no lower than 10. Anything less and you may not receive an accurate portrayal of FC loss (by percentage), even if it’s only 1 ppm.

    That will help to confirm if you have an active algae issue going on right now.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
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    Re: Dropping CYA by Overflowing?

    Ok. So let me repeat and see I understood it right!

    Today after the sun goes down, i have to make the FC as high as SLAM level, which i think would an FC of 28. And tomorrow after the sun sets i do the measurement again and see and see where my FC is at, right?
    Purex Titron FNS DE Filter 25000 gallons approx.
    Century A.O. Smith B855 56Y 2HP Motor. 40x25 (approx). Plaster surface.
    TFT-100 Test Kit.
    Rainbow Lifeguard 320.
    DX5+S Cleaner.

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    Texas Splash's Avatar
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    Re: Dropping CYA by Overflowing?

    Not exactly. You add chlorine and test tonight before bed (example FC of 28). Then in the morning, before the sun hits the pool, test FC right away. Hopefully you won't lose anymore than 1ppm of FC. If you did, then you probably have something in the water eating your chlorine and need to do a SLAM.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
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    Re: Dropping CYA by Overflowing?

    Oh... got it! Let me try it. I will post back after tomorrow with my results.
    Purex Titron FNS DE Filter 25000 gallons approx.
    Century A.O. Smith B855 56Y 2HP Motor. 40x25 (approx). Plaster surface.
    TFT-100 Test Kit.
    Rainbow Lifeguard 320.
    DX5+S Cleaner.

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    Re: Dropping CYA by Overflowing?

    I think you got the math backwards......11 gallons over / 31 days comes out to 42-45 ounces per day. I go through a gallon about every 2 days during the hottest part of the summer.
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    Re: Dropping CYA by Overflowing?

    Woah! That's like 15 gallons a month!
    Purex Titron FNS DE Filter 25000 gallons approx.
    Century A.O. Smith B855 56Y 2HP Motor. 40x25 (approx). Plaster surface.
    TFT-100 Test Kit.
    Rainbow Lifeguard 320.
    DX5+S Cleaner.

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    Re: Dropping CYA by Overflowing?

    1 gallon of 8.25% bleach in 25,000 gallons only raises the FC by 3.5 ppm which is why one would expect to add a gallon at least every 2 days (that would be 1.7 ppm FC per day). 12.5% chlorinating liquid (if available) would be less volume and weight because it is more concentrated -- it would be about 30% less.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
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    Texas Splash's Avatar
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    Re: Dropping CYA by Overflowing?

    Hellstorm, is it too late to modify my math from post #8? Obviously my calculator malfunctioned, or my two opposing thumbs got in the way. . As noted, I calculated backwards, so 11 gal divided by 31 days is more like .35 gal per day. That's pretty darn good actually I would say. I also go through about 1/2 gal or so per day. If you can monitor and keep FC loss between 2-4 ppm per day, you are doing well.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

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    Re: Dropping CYA by Overflowing?

    Cool! I think i should be alright with regular maintenance then!! Now I only have to get a robotic pool cleaner. Waiting for some sales on labor day!
    Purex Titron FNS DE Filter 25000 gallons approx.
    Century A.O. Smith B855 56Y 2HP Motor. 40x25 (approx). Plaster surface.
    TFT-100 Test Kit.
    Rainbow Lifeguard 320.
    DX5+S Cleaner.

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    Mod Squad tim5055's Avatar
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    Re: Dropping CYA by Overflowing?

    Quote Originally Posted by hellstorm2004 View Post
    Mine?
    Well its the only sports team i really care about!!

    Does dirt/debris eat chlorine up? Like added about 3.8 gallons of bleach around 08/22, to make FC of 12 from the CYA chart. I checked on Sunday and its was 4. That's about 8 days. Now it probably has gone to 0 FC with all the fresh water being added. I will test the water today and see where the CYA is at and add fresh bleach again.

    If i take the whole of August gone through about 11 gallons.
    But the football they are using is the wrong shape.....

    But, I digress - back to your pool.

    You should be testing and adding chlorine (bleach) every day, not taking the FC up high and letting it go back down. The stabilizer/CYA is protecting the chlorine, but only to a point. Any chlorine above that protected level is eaten quicker by the UV of the sun. You will use the least amount of chlorine by keeping an even level in your pool. Never go below the minimum for the amount of CYA in the pool, but don't take it up too high either.

    With a couple of weeks of daily testing under your belt you may find you know how much chlorine to add each day and just do it automatically, testing every second or third day.

    Only two things cause the chlorine level to drop, UV rays and organics in the water. Organics include leaves, bugs, bodily secretions - basically anything that was or is living.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    hellstorm2004's Avatar
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    Re: Dropping CYA by Overflowing?

    At least the ball touches the feet!!

    The was or is living thing is the problem. My house is beside a park and lots of trees surround it. Its full of dead leaves, flowers at the moment. I used to vacuum manually, but given up on it, to much work. Right now planning to get the Dolphin DX5+S, looked decent from the specs, after that i guess i should be pretty alright!
    Purex Titron FNS DE Filter 25000 gallons approx.
    Century A.O. Smith B855 56Y 2HP Motor. 40x25 (approx). Plaster surface.
    TFT-100 Test Kit.
    Rainbow Lifeguard 320.
    DX5+S Cleaner.

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    Mod Squad tim5055's Avatar
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    Re: Dropping CYA by Overflowing?

    Quote Originally Posted by hellstorm2004 View Post
    At least the ball touches the feet!!

    The was or is living thing is the problem. My house is beside a park and lots of trees surround it. Its full of dead leaves, flowers at the moment. I used to vacuum manually, but given up on it, to much work. Right now planning to get the Dolphin DX5+S, looked decent from the specs, after that i guess i should be pretty alright!
    Pools are work, no doubt about it...

    Leaving leaves, flowers and stuff like that turns the pool into a large tea cup. Tannins and other things steep out of them into the water just like the tea bag. Best to get them out rather then let them steep.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    hellstorm2004's Avatar
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    Re: Dropping CYA by Overflowing?

    That is very good way of putting it. I do clean it time to time, but not at the rate i was doing previously. Just waiting for the cleaner to arrive and take care of it!
    Purex Titron FNS DE Filter 25000 gallons approx.
    Century A.O. Smith B855 56Y 2HP Motor. 40x25 (approx). Plaster surface.
    TFT-100 Test Kit.
    Rainbow Lifeguard 320.
    DX5+S Cleaner.

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