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Thread: Conflicting opinion: Filling pool with hard or soft water?

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    Conflicting opinion: Filling pool with hard or soft water?

    I took ownership of a pool when we moved in 3 summers ago and I am finally getting serious about learning the ropes.

    When we moved in the sellers told us to bypass the whole house water softener when filling the pool. They said the pool builder told them the soft water would leech minerals/etc from the paint and/or plaster and ultimately shorten it's life and finish. I mentioned this to a pool tech who opened my pool and he said that isn't true.

    Certainly, off the cuff, I would think that softer water would be easier in terms of maintaining chemistry but I do not want to damage the paint or plaster.

    Incidentally, I am having some scaling issues which is why I bring this up although my CH is 250. I have been trying to lower my TA as pH is hard to keep down with the SWG but that is another issue I am battling now and my sense as to why scaling is happening.

    Thanks for a firm answer in advance.

    This morning.
    FC 5.5
    CC 1.0
    CYA 40 (just added to hopefully get to about 50 today)
    pH 7.5
    TA 130
    Temp 82
    19000 gal in ground, pebble tec. Sta-rite system 3 DE filter, Aquarite SWG, raypak 406A heater

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    NWMNMom's Avatar
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    Re: Conflicting opinion: Filling pool with hard or soft water?

    The reasons that soft water is better for your house and home is the same reason soft water is good for your pool.
    18x33x52 Buttressfree Seaspray (Wilbar) AGP - 1.5hp Pentair Maxim w/22" Pentair Meteor Sand Filter, Aqua Rite SWG System, Biltmore Walk In Steps - 2/4x20 Solar Panel Setup - Doheny Jet Drive (RIP -Pool Rover Jr) - finally hard plumbed the whole darned thing -
    Beats Driving to the Lake!

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    Richard320's Avatar
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    Re: Conflicting opinion: Filling pool with hard or soft water?

    Seems to me that adding some Calcium is a heckuva lot easier than getting rid of it. If I had a water softener, that's what I'd use to top off my pool! You can do the opposite - fill with soft, replenish with hard until CH gets near the limit, then switch back.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
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    Re: Conflicting opinion: Filling pool with hard or soft water?

    That's what I thought - thanks. Of all things, I do NOT want to replaster before I have to!

    Much appreciated!

    Evan
    19000 gal in ground, pebble tec. Sta-rite system 3 DE filter, Aquarite SWG, raypak 406A heater

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    Mod Squad Bama Rambler's Avatar
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    Re: Conflicting opinion: Filling pool with hard or soft water?

    If you'll keep the levels near the recommended values and the CSI near to just below zero you won't harm your plaster or have scaling issues. The best thing is that the Pool Calc figures all this for you and all you have to do is maintain.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
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    Re: Conflicting opinion: Filling pool with hard or soft water?

    It is odd that you are having scaling issues since your CSI is around +0.1 but if you are referring to scaling in the saltwater chlorine generator cell, then that makes sense and is why one often runs the CSI slightly negative. So yes, lowering your TA would help. You could also consider using 50 ppm Borates in your pool since that acts as an additional pH buffer that cuts the pH rise in the salt cell roughly in half so helps to prevent scaling.

    The main reason to have the auto-fill go through the water softener is that evaporation and refill adds whatever is in the fill water to your pool since evaporation only removes water. So if most of your water addition from the auto-filler is due to evaporation, then using softened water makes sense so that you don't keep increasing CH over time. If most of your water addition is due to making up for water dilution from backwashing, carry-out, splash-out, then using the original water might be OK if the water isn't extraordinarily hard (i.e. with a CH higher than the water in the pool).
    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
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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    Re: Conflicting opinion: Filling pool with hard or soft water?

    Hi Chemgeek

    The scaling is actually on the pool walls. It is hard, white streaks almost like a bird dropping on the side of a car or dripping candlewax. I assume it because my pH tends to stay high (7.8) if not aggressively driven down. Recently it got to 8.0 and I wonder if that is what precipitated the new scaling - no pun intended. I went through the pool with a scrungie and goggles and got most off pretty easily although some of it is too hard to remove without my worrying about damaging the plaster.

    I am hoping that by increasing my CYA level, and then reducing TA and adding borates, that the pH will stabilize.
    19000 gal in ground, pebble tec. Sta-rite system 3 DE filter, Aquarite SWG, raypak 406A heater

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    Re: Conflicting opinion: Filling pool with hard or soft water?

    Ah, that make's more sense, especially if the pH got closer to 8.0 since the CSI would approach +0.6 at that point. Yes, lowering your TA should help. The Borates should slow the rate of pH rise, but not the amount of acid you need to add unless you have nascent algae growth and are able to turn down the SWG on-time as a result.
    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
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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