Common Pool Water Problems

List of common pool water maintenance problems.

1. Algae growth.
A real classic. Algae are one of the most common problems you will face sooner or later. Although there are more than 20,000 different species, the ones you will normally find in the pool are only a few types of them, which makes standard treatments, such as the ones we are about to see, usually very effective.

Types of algae that frequent swimming pools:

1.1. Green Algae. They cloud the water, stick to the walls and float around the pool.

1.2. Mustard Algae: Normally they adhere to the wall, so they do not usually soil the water.

1.3. Black Seaweed: They also usually appear on the wall. They are the most difficult to eliminate.

Preventive treatment; algae:
It must be done consistently. Algae are persistent and should also be prevented; they must be taken into account in any maintenance plan.

There are many products to prevent their appearance; you can opt, for example, for the use of Multiaction products (which normally contain anti-algae, you should make sure of that) or add the anti-algae directly and regularly.

The frequency and quantity of the product will vary depending on the size of the pool and the manufacturer’s instructions.

Example: In a 100 m3 pool using AstralPool Antialgae you should put 0.5 L per week. Visit the product sheet for more information about this product: AstralPool Liquid Algae Remover.

Palliative treatment; algae:
When the preventive plan fails, and the algae appear whether it is green, mustard or black algae, it is advisable to start by thoroughly brushing all surfaces where they have been deposited and pass the cleaner with the selector valve in the empty position so as not to contaminate the filter. This step is not necessary but will shorten the treatment time and save chemicals.

The pH of the water must then be measured. The appropriate value is between 7.2 and 7.6. If you don’t have it regulated, try to get it up to the proper level as soon as possible. For this purpose, we offer pH Plus or pH Minor products, depending on whether you need to raise or lower it.

After the pH regulation you need to do a shock treatment with dichlorine (Rapid Chlorine). Following the manufacturer’s instructions, add the recommended dose for the m3 of your pool. For example for 100 m3 you should add 1.5 kg of Granulated Dichloro PM-503.

In addition to the shock treatment with Dichloro, you should also do the same with the Flocculant (see this product by clicking here) so that all the dirt goes to the bottom and is easy to remove with the cleaner.

After this, start the filtration system for 24 hours (preferably in the recirculation position) and then brush and vacuum again as recommended before starting the chemical treatment (with the valve in the empty position).

Finally, make a shock treatment with an algaecide, for example the already mentioned Astralpool Algae Remover.

2. Cloudy water.
The turbidity of the water in the pool is due to the presence of suspended particles, these particles are too small to be trapped in the filtration system. Turbidity can be a symptom of different problems and therefore have different solutions.

The most common causes are:

2.1. Cloudy water from algae. An incipient presence of algae may give the sensation of turbidity without the algae being clearly visible.

2.2. Uncompensated turbid water PH. The pH is one of the parameters that should be monitored more closely (it is easy and economical to do this for example with the Cl/Br/pH Eco Analyzer kit) and to keep it between 7.2 and 7.6. A high or low pH will bring problems to the pool and may be the cause of its turbidity.

2.3. Cloudy water from suspended particles. In any case, the turbidity of the water is always caused by the presence of particles that neither dissolve nor settle on the bottom and are not large enough to be retained in the filter. These small particles (whatever they may be from nature) float freely and cloud the water.

Preventive treatment; turbidity:
Poor filtration is often the source not only of this but also of many other problems in the pool. Make sure you are doing a good job of filtration and that your equipment is well sized. For more information on this, visit this other article: Pump and filter calculation for the pool.

Flocculation must be carried out throughout the bathing season.

As with algae, there are maintenance products that include flocculants (multi-action products). If you do not use one of them, you should add a dose of flocculant at least weekly. You can use for example: Liquid Flocculant for AstralPool Swimming Pools

Palliative treatment; turbidity:
If the pool is already cloudy the first thing you should try to do is to find out what it is, it will not always be possible but if you do, the path to recovery will be much easier… To do this, you can make the following inquiries:

Can suspended particles be distinguished? If this is the case, for example, there are clearly colonies of algae, make the specific treatment for this problem.
Is the pH within the proper parameters? If not, you should restore it as soon as possible.
If you are unable to find out why the problem starts with the pH regulation, once the appropriate parameters have been met, apply a flocculant treatment as follows:

With the filtration equipment stopped and no bathers present, add 10 ml. of Liquid Fluculant for each m3 of water.
After about 8 hours the product will have done its job (if the pH is not regulated the Flocculant does not work) and the suspended particles should be on the bottom, forming a visible layer; then pass the cleaner to collect and remove everything. This must be done, as previously indicated for algae removal, with the selector valve in the “drained” position.
The water should now be much clearer although you may have to repeat the process for more than a day. Before wiping the cleaner, look at the layer that has formed on the bottom to try to figure out what it is. If it is non-organic matter, you only have to follow the flocculant process as many times as necessary until everything is removed. If it is organic (algae usually) you should also do an anti-algae shock treatment.

3. pH mismatches.
We have already referred to it in all the previous sections because it is really very important. With the pH out of control the maintenance products lose much of their effectiveness so it will be very difficult to solve any problems that may arise.

Besides this the pH (low or high) is in itself a problem. The level should be between 7.2 and 7.6 at all times.

If the pH level is high, flocculation worsens, the effect of disinfectants decreases and eye and skin irritation may occur.

If the level is too low the water will be corrosive to metals, will worsen flocculation and will cause eye and skin irritation.

4. Lime incrustations.
Lime incrustations are visible to the naked eye, appearing on walls and fittings, white limescale deposits that make the surfaces rough and rugged.

Preventive treatment of lime deposits:
A high lime content in the pool water is the obvious problem when these deposits occur, but it is not the only cause of their appearance. A high pH will cause the appearance of these, so maintaining the appropriate level (between 7.2 and 7.6) is the first step to avoid them. Removing excess lime before putting the water in the pools would be a very effective preventive treatment, but in many cases this is not economically viable. In these cases you should use an Antiscale in preventive doses according to the manufacturer’s instructions. For example, for Astralpool it would be 0.5 litres of product per 100 m3 of water per week.

Palliative treatment; limescale deposits:
If the lime deposits have already appeared, the first step is, as usual, to regulate the pH level. Once this has been achieved, all we have left to do is to use anti-lime, with the same product we proposed for preventive treatment, the shock dose would be ,5 litres per 100 m3.


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