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Water quality in architectural fountains

Posted by on in Componentes de las Fuentes Ornamentales
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Sistemas de filtrado par a fuente seca

For the proper functioning of Architectural Fountains and for their component parts to provide a good performance along the years, it is important to use the right water in order to prevent failures and a rapid wear of the parts that make up the Fountain. As a general rule the water must have the same cleanness, clearness and acidity characteristics and the same calcium proportion as safe drinking water. Now we will describe those characteristics in a shortened way. More information will be provided later. Read more

  • - The pH must be between 7.2 and 7.6
  • - The impurity content of any kind must not be over 50 g per m3 of water.
  • - The water hardness must not be over 180 mg of Ca Co3 per 1 liter of water.
  • - The chlorine amount must be under 125 mg per 1 liter of water.
  • - The water temperature must be between +5ºC (41ºF) and +35ºC (95ºF)

Water pH

La corrosión por exceso de acidez en el agua
Figure 1
This detail, which is usually not known and is barely mentioned, is often the reason for many of the architectural Fountains’ component parts –electro-pumps, nozzles, submersible lights, pipes, etc.- to get intensely corroded and eventually stop functioning in a timeframe shorter than a year. This is because most of these parts are made of Bronze, Brass, Tombago, AISI 304 stainless steel, etc., metals which do not tolerate high acidity. Water is considered neutral when its pH is of 7 – if the pH is over 7 it is considered alkaline water. Fig.1 shows the corrosion of a ø ½” Cascade Nozzle after 7 months undergoing the action of very acid water. .

 pH is an abbreviation of potential hydrogen and the normal scale of value can be between 0 and 14, being 7 the value of a neutral solution such as water. If the value is between 0 and 7 the solution will be considered acid, while if it is between 7 and 14 it will be considered basic (or alkaline). A good way to make an approximate pH measurement is by using a test strip, also known as litmus paper strip (Fig. Nº 2). When put into water, the paper strip changes its color so it can be compared with a scale of colors printed outside the packaging. Each color indicates the pH quite accurately. The price of these tests is usually not higher than $1.

Analyzer test kits for pools are also quite reliable. They provide quite approximate values and are not expensive. See Figure 3.

In general, when the pH value is over 8 water gets cloudy and can promote deposits in Pipes, Nozzles, etc. It can cause irritation of eyes, ears, nose and throat too. Also, if the pH value is over 8 there is no point in adding chlorine to water as such high pH value will prevent it from acting.

La corrosión por exceso de acidez en el agua Figure 2La corrosión por exceso de acidez en el agua Figure 3

 

 

Impurities in water

Filtro compacto con arena de Silex Figure 4If the water shows a high impurity content (+ than 50 gr/m3), this fact will cause deposits and blockages at the jet-outlet nozzles (especially in those with small diameter) and the pump impeller, where they are constantly deposited. So their performance will suffer and the output current will be reduced. So it is advisable that the water of the Architectural Fountains gets filtered, just like the water of a pool. For its maintenance it is good to add a flint-sand Filter or a similar device (Fig Nº. 4) that can filter all the water in less than 4 hours, on a daily basis. As these Fountains’ total water volume is small (they are not very deep), the water Purifier can be a small low-price unit which will yet make it possible to have clean, clear and impurity-free water. It is advisable to leave an electrical outlet in the Fountain’s bottom in order to connect a cleaning device that will absorb the bottom dirt.

In Fig. 5 we can see accumulations of dirt deposited into an electro-pump. If this dirt gets solidified, it can eventually break the Rotor’s supports.

La Bomba puede verse afectada por la suciedad en su interior
Figure 5

Water hardness

Water can be classified by its hardness, on the basis of the calcium and magnesium-salts amount that contains. This contain is always measured in Ca Co3 mg per 1 liter of water  (mg/ liter CaCo3).

In Architectural Fountains it is not advisable to use water with hardness over 90 mg/liter Ca Co3 (moderately hard water).

Thus, in the following table the mg/l correspond to Ca Co3:

Classification of water according to its hardnessCaCo3 mg per liter of water
MinimumMaximum
Soft water 0,0 17,0
Moderately soft water 18,0 59,0
Moderately hard water 60,0 119,0
Hard water 120,0 179,0
Very hard water More of 180

La iluminación se puede ver afectada por la cal
Figure 6

If the water used in the Architectural Fountains is hard or very hard, it will cause salt deposits in the submarine lights and therefore they will provide less light with the same energy expenditure (see Fig. Nº 6). It will also promote calcium deposits in the screw-in connectors of the pipes, Nozzles, etc. so they will be more difficult to change or repair. These salts are especially harmful for the inside of Pumps, Pipes, Electro-Pumps etc., where salt deposits will block the water access, consequentially decreasing the flow and the operating pressures. This can lead to an eventual breakage of the elements.

Es aconsejalbel un descalcificador cuando el agua sea dura Figure 7 This is especially serious in electro-pumps where they can eventually stiffen the rotor, leading to its breakage of to the breakage of any of the impellers’ vanes. These deposits are especially dangerous in winter, when many Architectural Fountains are disconnected because of low temperatures. Salts deposits accumulate inside the electro-pumps, where they harden and create a crust that wields the rotor to the Pump’s casing. Thus, the Pump gets totally unusable.
For all these reasons, in installations where water is very hard it is advisable to mount resin-softeners that interchange calcium and magnesium ions for sodium or hydrogen ions, causing the water to get softer (see Illustration 7).

 

Chlorine use in Architectural Fountains

Although the use of chlorine in Architectural Fountains is not very advisable (as it attacks the metals Nozzles, lights, etc. are made of), this risk practically disappears if the dose is not over 5 mg of active chlorine per liter of water. Chlorine is the most used product for water disinfection, as it makes it possible to eradicate most of the microbes, virus, bacteria and germs responsible for many diseases. Its bactericide action is produced by the oxidation of the organic particles present in water (virus, bacteria, etc.). For the chlorine to be effective the water must be clean and clear, because if there are impurities its bactericide action will be weaker. 5 mg of active chlorine per 1 liter of water is a sufficient dose for clear and clean waters with a pH under 8.0. Water must sit for at least 30 minutes if its temperature is between 10º and 18º C (50ºF and 64.4ºF). This timeframe must be increased up to an hour if the water temperature is under or over the stated values. There are many water-soluble products that contain chlorine.

Water temperature in Architectural Fountains

This is quite a relevant fact, especially with temperatures under 0ºC, because of the bad consequences deriving of the freezing of water (it can lead to breakages in pipes, electro-pumps, Nozzles, etc.). It must be taken in consideration especially when using LED lights, as they are very delicate and do not withstand temperatures under 5ºC (41ºF) or over 35ºC (95ºF)

So it is quite advisable and almost compulsory to dismantle these elements in countries with very cold winters or very hot summers. Anyway, LED or Incandescent lights must never be switched on if they are not located underwater, or water jets are not falling on them and cooling them. It is essential that the electric control panel mounts a switch to control the lights and switch them off when there is no water falling on them. The same must be done in Dry Fountains, where the Submarine Lights must only be switched on when the water jets are cooling them.

This detail, which is usually not known and is barely mentioned, is often the reason for many of the architectural Fountains’ component parts –electro-pumps, nozzles, submersible lights, pipes, etc.- to get intensely corroded and eventually stop functioning in a timeframe shorter than a year. This is because most of these parts are made of Bronze, Brass, Tombago, AISI 304 stainless steel, etc., metals which do not tolerate high acidity. Water is considered neutral when its pH is of 7 – if the pH is over 7 it is considered alkaline water. Fig.1 shows the corrosion of a ø ½” Cascade Nozzle after 7 months undergoing the action of very acid water.
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Comments

  • Guest
    Chandramohan Balakrishna Thursday, 01 June 2017

    Dear Mr Valesco
    The above article is very useful and informative on various parameters of water that is to be used in
    architectural fountains.
    Can you give us your suggestion about the use of Ozone instead of chlorine for use in disinfecting the water. I believe that Ozone injection in the circuit will enhance the quality and as well reduce the residual solids in the water .
    What is your advice?

  • Guest
    Ursula Evans Thursday, 01 June 2017

    Very interesting and informative. Thank you

  • Guest
    Cristian Ghergu Saturday, 03 June 2017

    Excelent! I used to pick up informations from people building water pools, but many of them keep it to themselves. A documented article on this subject is quite wellcome! Good idea! Keep it on!

  • A.Velasco
    A.Velasco Sunday, 04 June 2017

    Hello Cristian,
    Thanks very much for your comments.
    Regards,

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Guest Monday, 23 October 2017

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