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Thread: A little help with my chemistry, please!

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    A little help with my chemistry, please!

    Hi all,

    I'm a little over 1 month into my brand new pool (details in sig). I've been diligently handling the pool chemistry and I added the salt just over 1 week ago since I was supposed to wait 28 days for the pebble to cure. I followed PoolMath and bought 18 bags of salt but so far I only put 16 in. I knew it would take a little time for the salt cell to register so my plan was to watch it for a week or so because I had to go out of town the next day for 4 days. I was surprised to see how the Hayward SWG number in Omnilogic drifted up over time during that week. I targeted 3400, and right now the diagnostic says instant salt 3400, average salt 3700 and back on the main screen it says 3679. Since I didn't put all the salt in, I'm surprised it's that high. I bought an AquaChek salt test strip and it showed 3330 last Thursday. Anything to be concerned about here? I hope I didn't over do it?

    I just tested my water and here's my current reading:

    FC 7
    CC 0
    PH 7.6
    TA 110
    CH 175
    CYA 80
    Temp 67
    Salt 3330

    This resulted in a CSI of -.45, which seems to be in the acceptable range per PoolMath. Any concerns/

    I feel like I need to get the TA down to 90 and the CH up to 350. Before I start, I thought I'd ask for feedback. My TA has been steady around 110 the whole time so I thought I'd push the PH down to 7.2 (from my previous target of 7.5) for this week and see what happens to TA. CH has also been low the whole time so I'm thinking it's time to make it move.

    I appreciate your help/advice in advance. I love this place!

    Greg
    Completed 8/26/16: Rectangular pool 42x20 and spa 10x8, 27,000 gallons, IG, Pebble Tec (Sheen) White Diamonds, Hayward 700sq ft. cartridge filter, saltwater cell, (3) Hayward Ecostar VS pump, 500k heater, (2) 2' Sheer Descent, 3 Hayward Colorlogic pool lights (+1 spa), 2 Colorlogic 320 lights (Baja/water feature), Omnilogic automation, TF100 Testkit
    New Pool Build - Porter Ranch, CA

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    Re: A little help with my chemistry, please!

    Are you planning to heat any time soon?

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    Re: A little help with my chemistry, please!

    Quote Originally Posted by JamesW View Post
    Are you planning to heat any time soon?
    The spa, yes. Not the pool though. I heated it once from 73-82 for one day and I think it cost $100. Why do you ask?
    Completed 8/26/16: Rectangular pool 42x20 and spa 10x8, 27,000 gallons, IG, Pebble Tec (Sheen) White Diamonds, Hayward 700sq ft. cartridge filter, saltwater cell, (3) Hayward Ecostar VS pump, 500k heater, (2) 2' Sheer Descent, 3 Hayward Colorlogic pool lights (+1 spa), 2 Colorlogic 320 lights (Baja/water feature), Omnilogic automation, TF100 Testkit
    New Pool Build - Porter Ranch, CA

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    needsajet's Avatar
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    Re: A little help with my chemistry, please!

    Your TA will come down on its own over time due to acid additions, and it's best not to run too negative a CSI when heating. If frequent acid additions are bothering you, then yep, lower the TA by going to a lower pH, but be aware your CSI will be more negative and not ideal for the heater. Adding some calcium is a good idea to bring your CSI up, and -0.3 to -0.1 is a good range.
    12k IG salt; glass beads in plaster; K-2006C, K-1766, CCL, and Aussie 4in1 (HTH); Pentair Eco800 1.2HP VS; Zodiac SWC 1.3 lb/day (25 g/hr); 25" filter recycled glass; OKU solar panels; 1/2 HP solar pump; Rebel (Warrior) pool cleaner; FlowViz; prior pool AG 10k | Read Before Posting to get the best possible advice | ... and this helped me a lot!: TFPC for Beginners

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    Re: A little help with my chemistry, please!

    Quote Originally Posted by needsajet View Post
    Your TA will come down on its own over time due to acid additions, and it's best not to run too negative a CSI when heating. If frequent acid additions are bothering you, then yep, lower the TA by going to a lower pH, but be aware your CSI will be more negative and not ideal for the heater. Adding some calcium is a good idea to bring your CSI up, and -0.3 to -0.1 is a good range.
    Thanks, I noticed that the CSI would become more negative with the lower TA. Perhaps that's not the most important first step. I think I will work on the CH first.

    Any concerns with my salt levels? Right now OmniLogic is reporting instant: 3300 with average: 3700ppm in the diagnostic but the salt level one screen back says 3679ppm.

    Thanks,

    Greg
    Completed 8/26/16: Rectangular pool 42x20 and spa 10x8, 27,000 gallons, IG, Pebble Tec (Sheen) White Diamonds, Hayward 700sq ft. cartridge filter, saltwater cell, (3) Hayward Ecostar VS pump, 500k heater, (2) 2' Sheer Descent, 3 Hayward Colorlogic pool lights (+1 spa), 2 Colorlogic 320 lights (Baja/water feature), Omnilogic automation, TF100 Testkit
    New Pool Build - Porter Ranch, CA

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    Re: A little help with my chemistry, please!

    I would add that the most accurate indicator of your salt is PoolMath. If you have XXXX gallons of pool water, and you put in XXX lbs of salt, The result will be XXXX.

    That's bulletproof regardless of what tests and readouts say.

    Next, I would leave ALL your parameters alone. See what the trend is. If your pool stays where it is (CH will creep up in almost every case), leave everything alone. It's when you see trends in the wrong direction, make the appropriate changes.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: A little help with my chemistry, please!

    Thanks, Dave. I'm pretty confident on the pool volume because I used a metering device when I was filling it. What I could be missing is any salt that may have already been in the water? I didn't test it before adding. I'm hesitant to add the other two bags with the readings I'm getting right now. I'm definitely happy to keep things the way they are and will do so for a bit longer. Given that my CH is 175 vs. a target of 350-450, it just seemed really low but I don't want to create any problems of things bouncing all over the place. It's fairly stable right now but I didn't want that CSI to go too negative. I suppose I could be over thinking it.

    G

    Quote Originally Posted by duraleigh View Post
    I would add that the most accurate indicator of your salt is PoolMath. If you have XXXX gallons of pool water, and you put in XXX lbs of salt, The result will be XXXX.

    That's bulletproof regardless of what tests and readouts say.

    Next, I would leave ALL your parameters alone. See what the trend is. If your pool stays where it is (CH will creep up in almost every case), leave everything alone. It's when you see trends in the wrong direction, make the appropriate changes.
    Completed 8/26/16: Rectangular pool 42x20 and spa 10x8, 27,000 gallons, IG, Pebble Tec (Sheen) White Diamonds, Hayward 700sq ft. cartridge filter, saltwater cell, (3) Hayward Ecostar VS pump, 500k heater, (2) 2' Sheer Descent, 3 Hayward Colorlogic pool lights (+1 spa), 2 Colorlogic 320 lights (Baja/water feature), Omnilogic automation, TF100 Testkit
    New Pool Build - Porter Ranch, CA

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    Re: A little help with my chemistry, please!

    Higher temperatures would increase csi. Therefore, you have to plan for higher temperatures to prevent scaling. Carbon dioxide also offgasses faster at higher temperatures, which causes ph rise.

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    Re: A little help with my chemistry, please!

    Over the past couple of years, I seem to notice folks who use csi worrying too much about their water balance.

    It's as if csi is the one magic bullet that will make your pool perfect. It's not and it won't. There are thousands of us who have never calculated csi and never will. Even so, we have crystal clear pools and go swimming just like everyone else.

    So, my contention is that keeping your pool within the suggested guidelines here at TFP (FC - CC - pH - CH - CYA) and you will never have a chemistry issue with your pool.

    Yes, I know there are some outlier exceptions where folks in the Southwest and Texas have trouble with their water source, but those exceptions are few and can be dealt with easily enough.

    So, this is just one opinion but I believe there is far too much attention to csi. I'm on my soap box but, yes, I believe you are overthinking it a bit. I think you can get within the parameters suggested (or understand better why you may not need to) here on TFP and enjoy your pool.

    btw, suggested CH is 250-400, I think.....don't shoot it up to 350.....it'll come up anyway.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: A little help with my chemistry, please!

    Thanks, Dave.
    Quote Originally Posted by duraleigh View Post
    Over the past couple of years, I seem to notice folks who use csi worrying too much about their water balance.

    It's as if csi is the one magic bullet that will make your pool perfect. It's not and it won't. There are thousands of us who have never calculated csi and never will. Even so, we have crystal clear pools and go swimming just like everyone else.

    So, my contention is that keeping your pool within the suggested guidelines here at TFP (FC - CC - pH - CH - CYA) and you will never have a chemistry issue with your pool.

    Yes, I know there are some outlier exceptions where folks in the Southwest and Texas have trouble with their water source, but those exceptions are few and can be dealt with easily enough.

    So, this is just one opinion but I believe there is far too much attention to csi. I'm on my soap box but, yes, I believe you are overthinking it a bit. I think you can get within the parameters suggested (or understand better why you may not need to) here on TFP and enjoy your pool.

    btw, suggested CH is 250-400, I think.....don't shoot it up to 350.....it'll come up anyway.
    Completed 8/26/16: Rectangular pool 42x20 and spa 10x8, 27,000 gallons, IG, Pebble Tec (Sheen) White Diamonds, Hayward 700sq ft. cartridge filter, saltwater cell, (3) Hayward Ecostar VS pump, 500k heater, (2) 2' Sheer Descent, 3 Hayward Colorlogic pool lights (+1 spa), 2 Colorlogic 320 lights (Baja/water feature), Omnilogic automation, TF100 Testkit
    New Pool Build - Porter Ranch, CA

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    Mod Squad pooldv's Avatar
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    Re: A little help with my chemistry, please!

    Agreed, if you can keep all of your parameters within TFP guidelines then the CSI will take care of itself. It is when CH or TA creep outside of recommended levels that we need to start paying attention to CSI.
    Pool School - Recommended Levels
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    2012 build and pics, 20k gal gunite, black onyx pebblesheen, OK flagstone, IntellifoVS, cart filter w/Pleatco, IC40 SWG, Solartouch, 5 12'x4' solar panels, HP50HA heat pump, 8mil solar cover, borates, TF-100 test kit, SONOS, Doheny's Discovery Robot, hot tub on bleach

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    Re: A little help with my chemistry, please!

    Quote Originally Posted by pooldv View Post
    Agreed, if you can keep all of your parameters within TFP guidelines then the CSI will take care of itself. It is when CH or TA creep outside of recommended levels that we need to start paying attention to CSI.
    Pool School - Recommended Levels
    That's sort of what I'm getting at. I can appreciate that a TA of 100 (or even 110) is pretty close to the upper guideline of 80 so maybe I don't need to worry and it'll come down over time. I keep hearing that but how long should one wait? Also, the recommended level for CH for TFP, SWG, plaster is 350-450 according to PoolMath. I wasn't so much looking at CSI until I saw a warning in PM that it could be corrosive to plaster. Given that my level of 175 is significantly less than the target, I thought I should get it closer. I can wait but not sure how long that should be and if that negative CSI is causing any harm in the meantime.

    I was just looking at the recommended levels and the chlorine/CYA chart...at a CYA of 80, why does the chart say FC 4 to 6 and PoolMath says SWG min 4 daily target 9-11. What should I follow?

    G
    Completed 8/26/16: Rectangular pool 42x20 and spa 10x8, 27,000 gallons, IG, Pebble Tec (Sheen) White Diamonds, Hayward 700sq ft. cartridge filter, saltwater cell, (3) Hayward Ecostar VS pump, 500k heater, (2) 2' Sheer Descent, 3 Hayward Colorlogic pool lights (+1 spa), 2 Colorlogic 320 lights (Baja/water feature), Omnilogic automation, TF100 Testkit
    New Pool Build - Porter Ranch, CA

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    Re: A little help with my chemistry, please!

    The CYA chart is simply saying that the minimum FC (never go below) is 4, so you should target 6. Pool Math says the FC goal for a SWG plaster pool with CYA of 80 is between 4 to 11. They aren't contradicting each other.

    i would probably shoot for around 7 myself.
    Kelly, Tampa FL
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    Mod Squad pooldv's Avatar
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    Re: A little help with my chemistry, please!

    Yes, I would raise CH to 300 or so. Depending on how fast your pH rises will determine how fast your TA will drop by adding acid. Or you can lower it following this process, Pool School - Lower Total Alkalinity
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