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With so many parts available, and so many different brands on the market today, we understand that you may have a question about the fittings for your particular whirlpool bath or hot tub.

As specialists in hydrotherapy systems we are well placed to answer your queries, and over the years we have found that our customers really appreciate the help and advice we can give!

Here are some answers to your frequently asked questions:


  • How do I maximize the life of a filter cartridge?

    • Clean the elements per manufacturers cleaning instructions
    • Never use a stiff brush to clean the media
    • Maintain your pool or spa water chemistry in proper balance
    • Alternate two sets of filter cartridges when cleaning

    For swimming pools, clean the cartridge when filter canister pressure reaches 8 PSI above the initial system or new cartridge starting pressure. For spas, establish a routine cartridge cleaning schedule based on the amount of spa usage. If Baquacil is used as a sanitizer, the filter element must be cleaned with Baqua Clean before any cartridge cleaner is used.

  • How can I tell when a Filter Cartridge needs to be replaced?

    In a typical spa, the culprit that plugs the media is perspiration and body oils combined with soaps, chemicals and very fine particulate. In a swimming pool, the loading is primarily debris along with suntan lotions and organic matter such as algae.

    Assuming the Filter is properly maintained and correctly sized to the pump, determining when the Filter Cartridge is exhausted depends primarily upon three factors:

          1) Shorter cycle time between cleanings,
          2) Low water flow rate and high differential pressure,
          3) Catastrophic failure such as a tear in the media or center core collapse.

    All three are dependent upon proper pool or spa water chemistry and following a routine maintenance schedule. Filter elements are plastic and should be handled and maintained accordingly.

  • What is the procedure to clean my filter cartridge?
    1) Remove the cartridge from the filter housing following the manufacturer’s instructions.

    2) Use a garden hose with a straight flow nozzle to wash down the filter element. Work from the top down,
        holding the nozzle at a 45 degree angle, and wash all the pleats with emphasis between the pleats.

    3) Rinse until all dirt and debris is gone.

    4) For all spa cartridges and elements used in swimming pools where perspiration, suntan lotions, and other oils  
        are present, soak the element for at least one hour (overnight is most effective) in:
            (A) a commercial filter cleaner or
            (B) one cup tri sodium phosphate (TSP) to five gallons of water, or,
            (C) one cup dishwasher detergent to five gallons of water.

    5) Rinse the cartridge again to remove oils and cleaning solution.

    6) If the filter has a coating of algae, calcium carbonate (residue from calcium hypo chlorite), iron, or other
        minerals, soak the cartridge in a solution of one part muriatic acid to twenty parts water until all bubbling stops.

    7) Rinse.

  • What are the differences between the different types of filtration systems?

    There's a lot of confusion about various filters, and many different opinions. Here are a few facts to consider:
    The first is that a pool can be properly maintained with any of the filter systems available: Filter Cartridge, Sand or Diatomaceous Earth Swimming Pool Filter Systems. Below is a brief description of each type.

    Filter Cartridge Filtration

    The economic low maintenance filter.
    This one is easy to understand. Water passes though a filter material and the filter captures the debris. This is just like the water filters used under your sink. Cartridges have much more available area to filter than sand. Most start at 50 Sq.ft and the majority of the cartridge filters sold are larger than 100 Sq.ft. Cartridge Filters are designed to run at lower pressure than sand. This puts less back-pressure on the pump and hence you get more flow and turnover for an equivalent pump size. Generally these filters have to be cleaned once or twice a season by simply hosing them off, so you don’t touch them as often. In terms of particle size filtered out, cartridge is somewhere between sand and DE.

    Sand Filtration

    The older style filter.
    Water is pushed through a bed of filter sand and removed through a set of lateral tubes at the bottom. The filter area of a sand filter is equal to the area of the filter itself. For example, a 24” filter will have 3.14 sqft of filter area. Only the top 1” of sand is actually used to filter the water. The principle behind this filter is that water is pushed through the filter sand, somewhat like an espresso machine. Dirty water goes in the top and clean water exits out the bottom.

    As the filter sand becomes plugged with debris from the pool, the pressure increases on the filter and the water flow drops. In order to clean the filter, you just run it in reverse and dump the waste water; this is referred to as “back washing” the filter. Once the filter is back washed, you move to the rinse mode and that repacks the sand and then back to filter. This has to be done manually every few weeks. From a hydraulics standpoint, a backwash valve is typically the most inefficient piece of equipment you can
    add to a swimming pool system. Should the sand ever become really dirty, it is easily and inexpensively replaced. In terms of particle size filtered out, sand is the lease effective method – it can allow smaller particles to pass back into the pool.

    DE Filtration

    Low-usage alternative.
    Diatomaceous earth is mined and is the fossilized exoskeletons of tiny diatoms. They are used to coat “grids” in the filter housing and act as tiny sieves to remove debris. They are very small and as such can filter out particles as small as 5 microns. Diatom filter area are sized between sand and cartridge – around 60-70 sq ft are most common. Once the filter pressure rises, the filter is back washed just like a sand filter and then “recharged” with more DE powder. Typically it is poured in a slurry into the skimmer and it then coats the filter grids. DE filters run at higher pressures than cartridge filters and as such can lead to some inefficiency and flow loss.

Whirlpool Baths

  • I think the button on my whirlpool bath is broken, how can I check?

    If your whirlpool bath is operated by a pnuematic push button on/off there are a number of simple checks you can do to see if it needs replacing.

    What is a pneumatic button?
    A simple pneumatically operated on/off button that turns a pump on or off. They work by sending a puff of air down an air tube which then latches a switch inside the pump which then activates the whirlpool system.

    Common problems that result in the button not working include the following:

    • The air tube becomes detached from the back of the button.
    • The rubber bellows inside the button may rot or degrade over time due to being constantly wet.
    • The air tube may become disconnected form the pump or the end of the air tube may become split, meaning there is a poor seal (sometimes easily solved by cutting the end of the tube & re-attaching)

    If the button and the air tube are all in good working order yet still the whirlpool won't turn on then the problem may be that the mechanical switch inside the top of the pump is broken
    A simple test for this would be to turn off the electrical power to the bath, pull the air tube off from the back of the button then blow down the air tube to see if you can hear the switch inside the pump clicking?
    If you can hear a clicking sound then you know that the switch is operational.

    Pnuematuc buttons are available in a range of sizes and colours.
    The important thing when looking to replace a button is to note the hole size in the bath so that your replacement will slot into place.

    See our range of Whirlpool bath buttons


  • What applications can the Argonaut pumps be used for?

    The Argonaut pump range is good choice for small to medium sized pools, spas, ponds or other recirculation systems.

    There are 6 different sizes to choose from
    They are available as single phase or 3 phase
    The Argonaut are self priming up to 3m

    One of the main features of these pumps is that they are silent running.

    The seal fitted on the Argonaut pool pump is suitable for a wide range of applications including chlorine, bromine, iodine and sea water (if flushed through with fresh water on shut down). 

    Argonaut Pumps

Air Blowers

  • Have the Genesis Air blower part numbers changed?

    In recent years the manufacturers Hydroair have changed the model numbers from GB__ to just G_ so be aware of that if you are replacing and older model.
    The model number can be found on the back of the blower Eg: G70-2NN-S

    So in general if you have GB50 you can replace it with a G50

    There are 13 different models in total
    Available in 500w – 1200W
    As heater or non heated
    Pneumatic or Electronic & with various speed settings.

    We stock the majority of these blowers at Hydrospares.

My Account

  • Whats my user name?

    When you created your account you'll have used your email address as your username.

  • What happens if I forget my password?

    You can request your password to be reset by entering your email address on the Forgotten Password page and we'll send you a link in order to reset it.

  • How do I track my order?

    If you've created an account with us then you can track your Hydrospares.co.uk order and view older orders online by logging in by clicking on the Login / register link on the top right of the screen.
    If you don't have an account then you can still track the progress of your order by entering your email address and order number in the Order Tracking box in the My Account/Login area.

  • How do I set up a Trade account?

    Simply go to the create an account page, fill in your details and tick the box 'I would like a trade account'.
    One of our team will review your details and respond to you within 24hrs.
    As soon as your account is set up then you will be able to log in and view trade prices.

  • What are the benefits of having a trade account?
    • Competitive trade prices
    • Order by 2.30pm for next day delivery.
    • Log in and place your order without having to re-type all your details
    • Save regular items to your Favourites list so they're easy to find next time
    • View your saved quotes and quickly turn them into orders

    create an account page or Log in

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