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Thread: Help with indoor pools

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    Help with indoor pools

    Little background I have been cleaning a few outdoor pools for a resort for a few years now. I have had no problems maintaining the water. But I have recently started cleaning cabins and I have been giving all the cabins with indoor pools. 1 is a salt water pool 1 is bromine pool other 3 are chlorine tabs. I use Taylor fas dpd 2006k test kit. So my main problem is high cya. I having a hard time finding a balance for chlorine. These pools are 2500 to 3500 gallons. I try to maintain my chlorine at 3ppm. But I'm finding that it's hard to maintain this level. I can turn the chlorinator on a 1 and it will be fine but then guest can check in and over use the pool and I come to clean it and have cloudy water. I turn it up to a 3 for next guest I come to clean it and may have a 6 or higher ppm. Then cabin may not rent for a few days and chlorine might get to 10 plus. I then turn it off to barely having it cracked open, only for next set of guest to use it a lot and bottom my chlorine back out. So not sure how find a proper balance with such small pool and not knowing how busy the pool is going to be. Now I have started to check my cya levels again and I'm in the 80 to 140 ppm range on the chlorine pools. This happening cause of how often I half to boost my chlorine. I'm using 3 inch trichloro tabs. One pool had some calhypo 3 inch tabs but doesn't have the right feeder and the hardness is 560. So how can I keep my cya levels from getting so high. These indoor pools get no sun light at all.

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    JasonLion's Avatar
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    Re: Help with indoor pools

    Indoor pools are more difficult to maintain than outdoor pools, and commercial pools are more difficult to maintain than residential pools, and small pools (where you aren't willing to dump out the water) are more difficult to maintain than larger pools.

    First off, there is just no way you can possibly use trichlor tabs on an indoor pool and expect anything to work out at all well without replacing all of the water regularly.

    Second, the correct FC level depends on the CYA level. If you don't keep the two in balance you are asking for trouble. With 36 posts, I would expect you to have heard that mentioned already.

    MPS can help significantly in indoor pools, but if you don't start with making much more fundamental changes you aren't going to get anywhere.
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    Re: Help with indoor pools

    How should I use mps and maintain my chlorine level? These are rental cabins and I only get to check pool on the day guest check out. These cabins may rent one night to a week or longer. That's why I use tabs. I need chlorine coming in all the time. Cause some people may use pool a couple times while they are there, others may use it every day that they are there and some times it may be a party group and pool can be over loaded. That's why I say I'm having hard time keeping my chemistry right. I know cya will make me need more fc when it gets crazy high. So far all pools look nice and clear but trying find a solution before I do get problems. So far sense I realized how high cya was getting I been draining the pool down slightly below skimmer hole cut out. And filling it back up. Its lowering cya but depending on how long guest stay it can rise before I get back to it again. Would switching to bromine be the best thing to do with indoor or try talk owners into swg?

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    JasonLion's Avatar
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    Re: Help with indoor pools

    If you are limited to using tabs you will need to replace significant amounts of water on a regular basis, say quarterly, or smaller amounts weekly.

    Use MPS to replace of about half of the chlorine you are currently using when recovering from heavy usage. MPS breaks down organic debris better than chlorine when there isn't any sunlight to help the process along. Chlorine without sunlight tends to cause CC accumulation, especially when there is heavy usage. MPS allows you to break down the CC without raising FC levels ridiculously high.

    Depending on your budget, ORP sensors with liquid chlorine feed systems are a much better long term solution. That will automatically vary the chlorine feed rate depending on usage. ORP has some significant problems, but is worth the trouble for variable usage indoor pools. A SWG will eliminate the need for regular water replacement, but it doesn't really solve the underlying problem of highly variable usage. Plus it is way too easy to get the FC level wildly too high in an indoor pool with a SWG, which can cause some serious problems of it's own.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: Help with indoor pools

    If you are in the 80 to 140 ppm CYA range for these indoor pools then the minimum chlorine level is 6 (for 80 ppm CYA) to 10.5 ppm (for 140 ppm CYA). Algae can still grow in indoor pools since the light that algae needs to grow does not have to be from sunlight. If the rooms with the pool are kept completely dark, then that would inhibit algae growth.

    The point is that with the higher CYA level you can have the higher FC level as a target so even under heavier usage the FC won't get too low. You should set your chlorine feeder to be the low background level of chlorine usage and you can then bump up the FC using chlorinating liquid or bleach after guests with heavy bather load have visited and can start with MPS first to minimize CC. That will minimize your CYA buildup. Of course, the other more automated solutions would be better, but you can do this manual hybrid as a compromise.

    If you use MPS, then you'll need the Taylor K-2042 test kit to distinguish between FC, CC and MPS.
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