Yes. Polyurea is highly resistant to both chlorine and salt water. The material is not attacked by the chemicals used in pool water, making it suitable for both classic chlorine pools and salt-electrolysis systems.
This makes polyurea particularly well suited to coastal pools, where salt in the air and water would normally age many materials more quickly.
Because the coating is seamless and closed, water and chemicals cannot creep underneath it anywhere. That prevents the damage that often develops with tiles and grout lines over time.
Resistance does not make water management less important. A correctly maintained water balance is still needed, both for your installation and for your own comfort. Overdosing chlorine or salt, and products whose compatibility is not established, fall outside the guarantee.
The coating also does not replace your salt-water system. That system keeps disinfecting the water, while the coating makes sure the shell can handle it for years. If you are unsure about a product, please ask us first.
We do this ourselves on the Costa Blanca: polyurea pool waterproofing
What salt water does to a pool
With salt electrolysis a cell produces chlorine from the salt dissolved in the water. The concentration is around four to six grams per litre, a fraction of seawater, but enough to attack materials that were not made for it.
Salt soaks into porous materials. In plaster and grout it crystallises as the water evaporates and breaks the pores open from the inside. That is why grout crumbles, natural stone around the pool turns white and screws and fittings that lasted years in chlorinated water start to rust.
A pool is only truly salt-resistant when everything that touches the water is: the shell, the edges, the metal parts and the equipment. The coating solves the first; the rest deserves the same attention during a renovation.
Why polyurea can take it
Polyurea is a closed, non-porous membrane. Salt cannot soak into it, so it cannot crystallise from the inside either. There are no joints for water and chemicals to seep down through, and the layer bonds across the whole surface so nothing can get behind it.
Salt and chlorine at swimming-pool concentrations do not attack the membrane. The same type of membrane is used in drinking-water reservoirs, irrigation channels and seawater tanks; in the latter the salt content is many times higher than in your pool.
The osmosis blisters that plague fibreglass pools, where water works its way through the gelcoat into the laminate, do not occur with polyurea: pool water does not pass through the membrane. Moisture can, however, come from the other side, out of a damp or not yet cured shell. That is why we only coat a dry substrate and why the primer acts as a vapour barrier.
Chlorine, shock treatment and pH: what is fine and what is not
A normally maintained water balance, with a pH between 7.2 and 7.6 and free chlorine of one to three milligrams per litre, does not stress the coating. A shock treatment after a party or a heatwave is no problem either, as long as the product dissolves and the pump is running.
What you should avoid: chlorine tablets or granules left lying on the floor. At that spot an extremely high concentration builds up that can bleach the top layer locally. Dissolve granules in a bucket first, or use the dispenser at the skimmer.
A pH that stays too low for weeks makes the water aggressive, for your equipment too. It eats at metal and takes the sheen off the top layer. Acid washing the shell, as is common with tiles and mosaic, is neither necessary nor sensible with a coating.
Switching to salt after the pool has been coated
That is perfectly possible. The coating does not notice the difference. What you do need to watch are the metal parts: ladders, the rings of the lights, the screws of skimmer lids and the fixings of the steps. Choose the highest grade of stainless steel for those and always have a salt system properly earthed.
The coping stones and the natural stone around the pool are the second group to watch. Salty splash water that dries leaves white deposits and flaking there. Impregnating the edges is therefore part of a proper conversion to salt.
We run the coating right up to the edge and around every pipe entry. That keeps the shell itself out of the discussion and focuses the maintenance on the parts that really are sensitive to it.
The waterline takes the most punishment
Under water a polyurea coating hardly wears at all. The zone that takes the most punishment is the waterline: that is where sun, evaporation and chemistry meet. Salt and lime settle there as the water evaporates, exactly as a glass of salt water leaves a ring.
On tiles and mosaic that deposit grips the grout and the pores. On a smooth, closed surface it stays on the outside and you wipe it off with a soft sponge and a mild, compatible cleaner.
High pressure, scouring pads and acid are unnecessary and unwanted here. They damage the top layer and take the sheen off, while the deposit simply comes away with a little patience.
What falls outside the guarantee, and why
We give a ten-year guarantee on the watertightness of the system under normal use and correct maintenance. Normal use means a water balance within the usual values and only products whose compatibility is established.
Outside the guarantee fall damage from overdosing chlorine or salt, from products whose effect on the coating is unknown, from pressure washing above the recommended values and from a pool left empty in the sun for a long period.
These are not exceptions to dodge the guarantee but exactly the situations in which every pool material suffers. A simple log of your water values makes any guarantee conversation easy for both sides.
Sea air, splash water and salt outside the pool
On the coast the salt is in the air as well. Roof terraces, balconies and pool surrounds in the first line from the sea get a daily film of salt aerosol. Concrete, grout and metal railings visibly weather faster there than a few kilometres inland.
A polyurea membrane does not weather from that, any more than it does under water. For a roof or terrace on a seafront that is one of the reasons to choose a closed layer rather than tiles with grout.
The metal details remain the weak point there too. Drain grilles, balustrade posts and fixings in ordinary-grade stainless steel rust by the sea within a few years; that is not a defect of the coating, but it is something to include in a renovation straight away.
Maintenance with salt and chlorine water
Check the pH and chlorine level weekly, and with salt also the salt level and the calcium hardness. An electrolysis cell gradually raises the pH, so with salt pools adjusting with a pH reducer is the most common task.
Wipe the waterline regularly before the deposit sets, rinse the edges with fresh water after hot days and keep the filter system clean. The coating asks for nothing more.
Do not leave the pool empty in winter. Groundwater pressure, drying out and sun put far more stress on an empty shell than on a full one, whatever kind of water is in it.
Salt or chlorine: does it matter for the choice of coating
Not for the coating. Both systems ultimately disinfect with chlorine, one from a jerrycan, the other from salt. Polyurea handles both, and you do not have to decide when the pool is coated.
For the rest of the pool it does matter, and we advise honestly on that. Salt is kinder to skin and eyes and means less lugging of chlorine, but it makes higher demands on metal and natural stone. Anyone who includes those parts in the renovation enjoys the benefit for years.
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