European Commission project  for your Life & the Environment click here ISO 9001 quality  company	Aquaculture, Water & Wastewater Treatment Environmental & sustainable water treatment to save the planet	| Contact us  | About us |  Search |  Shop ||
Web  sites  ]   | Home |   AFM  |  Ozone  |  Membrane filtration  | Swimming Pools |

How much to use

The pH of the water is adjusted by varying the amount of Magphlow in the filter. As an approximate guide, if it is desired to raise the pH from 5.5 to pH 6.8, approximately 0.25 to 0.75 kg of Magphlow are required per cubic metre of water treated over a 24 hour period. For example if the water flow is 100 cubic metres per day the amount of Magphlow required would range from 25 to 75kg.

The pH of water is a log scale, thus if it takes 300 kg to raise the pH of the water from 5.5 to 6.8, it could take 3,000 kg (ten times as much) to raise the pH to 7.8. It is virtually impossible to raise the pH of the water to levels greater than pH 8.3 since the magnesium will precipitate out of solution. This property also make Magphlow the ideal buffer to employ in marine hatcheries and recirculation systems.

In a marine system you can not use too much of the Magphlow product,   indeed the more you have in the system the more stable the pH.  As a guide we would recommend 1 to 2 kg of media per cubic metre of water treated per day.

In situations where the freshwater water is recycled, the amount of Magphlow media should be equivalent to 0.25kg of media for every cubic metre of water recycled per hour.   In a marine recycle system this figure should be closer to 0.5kg for every cubic meter of water recycled per hour.  For example,  in a marine system if the recycle flowrate was 50 cubic metres per hour,  there should be at least 25 kg of Magphlow media in the the recycled water.   

The above figures should be used only as a guideline since there can be a wide variation in the actual quantity required in any given system.  There is also a small quantity of sodium present in Magphlow media which will result in an initial high pH. It is therefore important to Read this before using the product.  For more information on pH control and regulation click

Heavy metal removal

On passage of water through a bed of Magphlow, the pH of the water will be increased and the solubility of metals will be reduced. Some of the metals may form a precipitate that will be removed by the sand of AFM filter media in the pressure vessel.

The micro environment on the surface of the Magphlow is pH 8.3. At this pH metals will have a tendency to form a precipitate on the surface of the Magphlow. The surface coating will eventually reduce the performance of the product. When this stage is reached the Magphlow bed must be back-flushed. During back-flushing the surface of the Magphlow along with the heavy metals will be removed. The surface cleaning works better when using AFM.

Fish farms

The pH of freshwater is very important to the health and vitality of fish and aquatic life. The salmonids, including Atlantic salmon, and Rainbow trout, are especially sensitive to pH. The critical stage is during egg incubation, egg hatch and through to first feeding. These periods normally coincide with the winter and spring months which are also the months when a low pH and acidic water can be expected.

Recycle systems, in recirculation systems the activity of the biofilters and fish will decrease the pH of the water rendering it more acidic. It is important that the system is buffered against acidic conditions and fluctuating pH since both factors will destabilize the biofilters and stress the fish. In marine system this is very important,  if the pH is allowed to fall below pH 7.8 it means that the carbonate buffering capacity of the  water has been exceeded and that the system could pH bounce.  It is essential that the pH is increased and maintained between pH 8.0 and 8.3,  Magphlow media has been used for over 10 years to achieve this task and has been proved to be the ideal process in both marine and freshwater systems.

Read this before using product

The Magphlow contains some magnesium hydroxide dust, it is therefore important that the product is washed to remove the dust prior to it being added to the system.The Magphlow media also contains a small amount of potassium and sodium hydroxide.   These hydroxides will dissolve during the first 24 hours of use giving a high pH. The Magphlow should therefore be soaked for 24 hours prior to use and then added in small portions over approximately 7 days until the desired pH is obtained. This policy will ensure the you do not stress the fish with a sudden pH shift, and that you obtain the pH desired.

You can reach us by e-mail at: howard@DrydenAqua.com
Copyright © 1997
Last modified: May 26, 2008