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Thread: ORP + pH Sensor + Acid pump - Optimum CYA levels .. or zero CYA?

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    Join Date
    Jun 2015
    Phoenix, AZ

    ORP + pH Sensor + Acid pump - Optimum CYA levels .. or zero CYA?

    Today, the PB and an official Hayward tech hooked up the Hayward Sense & Dispense system that has the ORP & pH sensor.
    We also hooked up the Stenner pump that is dispensing a diluted 2:1 ratio (2 H2O + 1 Acid) of 31.45 baume Muriatic acid.

    So, prior to configuring these, I had balanced the water to 7.5 pH, 5 FC, 0 CC, etc.

    The (awesome) tech from Hayward then spent a lot of time to configure the system.
    The system has been running for 3-4 hours now and I am seeing a constant 7.5 pH and 5 FC

    Upon reading extensively on the topic, there were topics that say that an ORP + pH system works well with a CYA level of ZERO!

    To the non-chem-geek like me, if we are constantly dosing the pool with acid trickles and SWG chlorine, albeit, in small amounts, why do we need CYA?

    In my new pool, I have 55 CYA and hope to keep it at that level, but is it beneficial to allow the CYA to come down in the future?
    2015 build (link)| 16.5 K gal | Salt Water | IG rect | 35'x16' | 568 sf | 105 ft peri | depth 3'-5' | PV3 in-floor | 2 Venturi skimmers | MDX+SDX drains | T-CELL-15 SWG | Hayward Ecostar VS pump | Hayward 7220 DE Filter | Aqua Cal Icebreaker Heat / Cool pump SQ166 | Hayward Sense & Dispense PH Controller| Omnilogic | Pebble Sheen Blue Surf | Ultra UV | Stenner acid pump | Coverstar Automatic | TF-100

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    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Tucson, AZ

    Re: ORP + pH Sensor + Acid pump - Optimum CYA levels .. or zero CYA?

    Because the summer sun will destroy the FC faster than the SWG can make it. Or if the SWG can keep up, it is working much much harder and shortening the life of cell.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
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  3. Back To Top    #3

    Join Date
    Mar 2007
    San Rafael, CA USA

    Re: ORP + pH Sensor + Acid pump - Optimum CYA levels .. or zero CYA?

    The active chlorine at the minimum FC/CYA ratio we recommend is equivalent to only 0.06 ppm FC with no CYA. You can't maintain that low an FC in your pool unless you have absolutely outstanding circulation and fast turnovers. There simply isn't enough chlorine around to handle any unusual events in the pool. The purpose of the CYA is not only to protect chlorine degradation from sunlight, but to enable having a reserve of chlorine while significantly moderating chlorine's strength.
    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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