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Bear of little brain

So, I’ve a salt water pool. OK.

Water evaporates (it was 39 oC today and windy). OK.

Salt doesn’t evaporate. So, the pool should get saltier, then I top it up and it reutrns to normal.

But I’ve just had to add 75 kg of salt (it’s around and about 75 m3 of water).

What is it that I’m missing?

I also want the idiots guide to salt water pools. Looking for pages says “shock it once a week” and “read the ph levels” and I need something that starts the level behind that. At least one level behind it. What’s this box? What’s that machine? What am I trying to do other than keep it salty? What’s the whole story? In a for idiots guide.

16 thoughts on “Bear of little brain”

  1. BiND in Schwerin

    I just dropped the whole post in to ChatGPT free version because I’d never heard of salt water pools. It answered most of your questions.

    ### Understanding Salt Water Pools: A Comprehensive Guide

    #### Basic Concept of a Salt Water Pool
    A salt water pool uses a salt chlorinator (or salt chlorine generator) to produce chlorine from salt added to the water. This chlorine is used to sanitize the pool, keeping it clean and safe for swimming.

    #### Key Components of a Salt Water Pool
    1. **Salt Chlorinator/Generator**: This device converts salt (sodium chloride) into chlorine through a process called electrolysis.
    2. **Pool Pump and Filter**: Circulates water through the filter and chlorinator, removing debris and distributing chlorine.
    3. **Salt (NaCl)**: Added to the pool water to reach the necessary salinity level for the chlorinator to function.

    #### How the System Works
    1. **Add Salt to the Pool**: Salt is dissolved in the pool water to achieve the correct salinity level (typically 2700-3400 ppm, parts per million).
    2. **Electrolysis**: The salt chlorinator converts salt into chlorine, which then sanitizes the pool.
    3. **Circulation**: The pool pump circulates water, ensuring even distribution of chlorine and filtering out debris.

    ### Maintaining a Salt Water Pool

    #### Why Did You Need to Add Salt?
    1. **Water Loss**: Salt doesn’t evaporate, but water does. If you lose water due to evaporation, splash-out, or leaks, the concentration of salt will remain the same. However, when you refill the pool with fresh water, the overall salt concentration decreases.
    2. **Backwashing**: When you clean your pool filter by backwashing, you lose some water, which also reduces the salt level when you refill with fresh water.

    #### Steps for Basic Maintenance

    1. **Check Salt Levels**: Regularly test and maintain the salt level. Most salt chlorinators have indicators showing if the salt level is too low or too high.
    2. **Monitor Chlorine Levels**: Ensure the chlorinator is producing adequate chlorine. Test chlorine levels using a pool test kit.
    3. **Balance pH Levels**: Aim for a pH between 7.2 and 7.6. Low or high pH can reduce chlorine effectiveness and cause skin/eye irritation.
    4. **Shock the Pool**: Occasionally, you may need to add a higher dose of chlorine to “shock” the pool, especially after heavy use or rainstorms.
    5. **Clean the Pool**: Regularly skim debris from the surface, brush pool walls, and vacuum the bottom.
    6. **Maintain Equipment**: Regularly check and clean the salt chlorinator cell, pump, and filter.

    #### Troubleshooting Common Issues

    1. **Low Salt Levels**: If the salt level is low, add salt as per the manufacturer’s recommendations.
    2. **Low Chlorine Production**: Clean the chlorinator cell and check for adequate salt levels.
    3. **Cloudy Water**: Test and balance the water chemistry, including pH, alkalinity, and calcium hardness.
    4. **Algae Growth**: Ensure proper chlorine levels, brush and vacuum the pool, and consider using an algaecide.

    ### Basic Steps to Setting Up and Using a Salt Water Pool

    1. **Install the Salt Chlorinator**: Follow the manufacturer’s instructions for installation. Ensure it’s connected to the pool’s circulation system.
    2. **Add Salt**: Calculate the amount of salt needed based on your pool volume. For a 75 m³ pool, you’ll generally need around 200-300 kg of salt to start.
    3. **Start the System**: Turn on the pump and salt chlorinator. Allow it to run continuously for at least 24 hours to fully dissolve the salt.
    4. **Test Water Regularly**: Use a test kit to monitor salinity, pH, chlorine, and other chemical levels.
    5. **Routine Maintenance**: Follow the regular maintenance steps to keep the pool clean and the water balanced.

    ### Simplified Routine Checklist

    1. **Daily**:
    – Run the pump and chlorinator.
    – Skim debris from the pool surface.

    2. **Weekly**:
    – Test salt, pH, and chlorine levels.
    – Adjust chemicals as needed.
    – Brush pool walls and vacuum the pool.

    3. **Monthly**:
    – Clean the chlorinator cell.
    – Backwash the filter.

    4. **Seasonally**:
    – Inspect all equipment for wear and tear.
    – Deep clean the pool.

    By understanding these basic principles and following a regular maintenance schedule, you can keep your salt water pool in optimal condition and enjoy crystal-clear, clean water throughout the swimming season.

  2. You can get a ph test kit from any pool supplier or bricos sometimes have them. What the ph should be, couldn’t tell you. It may be different from straight water +Cl/Br. For density, a hydrometer. Glass tube with a float in it. Sample water from various depths. Your top ups of fresh water will sit on the top of the salt water unless you’re running a circulator. So if you test at the surface, you may think you’re low on salt.
    Out of interest, why a salt pool? Isn’t the sea bad enough? Any health benefits claimed for them is straight woo*. Unless it’s the saving of energy keeping yourself afloat.

    *If it really did penetrate the skin then it’d work the other way. The water would suck all the water out of your blood since it’ll be at a higher electrolyte concentration.

  3. Oh & if you pump out, be careful where the water goes. Any rainwater drain is likely not connected to the sewers. It’ll be a weeper drain laid under your garden in a gravel filled trench. So you could end up doing what that Roman guy wanted to do to Carthage.

    Fun swimming pool story. One of our swimming pool company customers emptied his pool by pumping out onto the garden. Next morning his entire pool had come up through the terrace & was standing 2-3 ft proud. We built very good pools & the other word for an empty swimming pool sitting in a high water table is a boat. That pool took a lot longer to cut up & cart away than it did us to build it.

  4. BiS: “Any health benefits claimed for them is straight woo*.”

    Not entirely. The organisms that have evolved to live on our skin in a more-or-less mutually beneficial manner** are pretty salt-tolerant, whereas the ones that merely seek a Free Ride™ or worse are not.

    Thus giving your skin the occasional salt bath, be it the posh Dead Sea treatment, or merely working up a good sweat, letting it dry, and not showering it off immediately and cover it in perfumes and whatnot, is beneficial for your general health.

    ** The skin flora and fauna is just as interesting, and as little understood, regarding general health as the intestinal flora.
    Yet bugger up either of them, and you’re in for a world of hurt.

  5. This (from the AI effort above) . . .

    If you lose water due to evaporation, splash-out, or leaks, the concentration of salt will remain the same. However, when you refill the pool with fresh water, the overall salt concentration decreases.

    seems backwards in regards to evap. Leaks and splash-outs, sure, but evaporating water will leave a higher salt concentration behind.

  6. Forgot to add:

    Some salt is actually consumed in the chlorination process. That’s likely the source of your loss.

  7. > If you lose water due to evaporation, splash-out, or leaks, the concentration of salt will remain the same. However, when you refill the pool with fresh water, the overall salt concentration decreases.

    If you lose water due to evaporation the overall salt concentration *increases*, not remains the same. Yes, if you lose water by splashing the concentation doesn’t change. These are two separate things. This is why LLM’s such and you shouldn’t use it for anything.

  8. “Any rainwater drain is likely not connected to the sewers.”

    Checked that with the builders. The whole place (house, garden, also town) has separate storm sewers to normal. They actually built the system right in the first place.

    ” Isn’t the sea bad enough? ”

    We’re near Beja now. Sea’s a long way away.

  9. The ‘chloride’ bit of salt (sodium chloride) is being turned into chlorine by your ‘chlorine generator’ and eventually leaves the water as a gas (which is why you can smell it). The chloride leaving is balanced by carbon dioxide from the air dissolving in the water to form sodium carbonate (washing soda).

    So you need to top up those chloride ions every so often with more salt. I guess eventually if the water isn’t drained and replaced it gets saturated with sodium ions and won’t dissolve anything else.

  10. One learns something every day. Having had a company built swimming pool, I’d never heard of electrolysing salt water for chlorine. On just the bactericide front, what the hell for? For the pool we had in the villa – about 4 times the volume of Tim’s bathtub – I got through two tubs of chloro & a couple of gallons acid in a season. Under 100€. Heaven knows what 300kg would would cost you. And I presume Tim’ll still need the acid, because that’s to neutralise the calcite in the top-up water.
    But what concerns me is what do you do with 75m³ of brine if you want to get rid of it. You can’t put it in the ground because it’ll be there for ever. When their gardens start dying you’re neighbours would love you. Put it in foul the sewer? The local water company mightn’t be happy. That’s going to do their digester systems a power of. It’s a small community with a limited thru-put. Done in one go could poison it completely.
    Always think second order consequences.

  11. Incidentally, we went over to bromine. Cost a little more but you don’t seem to need as much. And you don’t have that horrible chlorine smell.

  12. You got something about salt water swimming, Tim? It really is just woo. Especially Grikath’s woo about skin flora & fora. It kills all of it. Why your skin gets fucked up if you spend a lot of time in the sea. We are not seals. Mammals & birds habitually go in salt water have oils in their fur or plumage. They never get wet.

  13. Former owner of salt- water pool with electro-sterliliser.

    The unit should have come with a guide to pH range for best operation and optimum salinity.

    You can get kits to measure pH and salinity. Test pH daily, keep it within parameters – test salinity every week.

    The electro-steriliser splits the NaCl into Na and Cl ions the latter to form chlorine, then pumps this into the pool, then later reverses polarity to reunite the Na and Cl ions. But choline is volatile so will leave the pool, particularly in warm weather, therefore the salinity will decrease with time.

    You should be able to programme the electro-steriliser to run continuously when the pump is running – start of season or if you see a few green patches appearing. Otherwise run it in 2 hour blocks twice a day to coincide with start of two 4 hour pump runs.

    Evaporation: topping up with fresh water will reduce salinity so occasional bag of salt might be required depending on rate of evaporation. Do you have a floating cover for the pool at night time or when not in use to reduce evaporation?

    You should not shock the pool unless disaster has struck, in which case turn off the electro-steriliser until the pool has cleared.

    If you do use chlor-shock – use a formula that does not have stabiliser. Stabiliser – slows rate of decay of chlorine to prevent loss – builds up if you use it frequently until eventually the pool becomes super-stabilised and the chlorine stops working. That means empty pool and refill.

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