Iron removal from borehole water 3

[backers]

Approx 8 yrs ago i had a pool built and noticed that the water from the borehole contained high levels of iron. The iron was removed from the pool water using a hired filtration system but it still left brown staining on the liner which took a forever to remove. Recently the pool was emptied and an Automatic top up system was introduced. Now i am worried that the liner will be stained when refilled. I intended to use manganese greensand as the filter media but when i checked the cost it was over £625.00 per 25lb bag. Is there a more cost effective alternative. The house has a completly separate water filtration system (Kinetico)which could not handle the volume of water the pool requires.
Thanks for taking a look. I hope someone could help on this matter

 

[orenda1168]

You might consider application of an iron stain prevention product for pools/spas that will chelate the iron and maintain it in a water soluble state. There are a number of these products available to the recreational water market, some of which should be stocked at your pool supply store.

Orenda

 

[backers]

Thanks Orenda. i Will try this when the pool is ready to be refilled

 

[bimr]

You probably can use regular filter sand in the filter. Filter sand will also remove the iron. The chlorine in the pool should oxidize the iron and the filter will remove it.

 

[orenda1168]

Bimr:

Generally this removal procedure does not work because pool water pH is not sufficiently high to drive the oxidation of iron compounds to the insoluble hydroxide state.

Orenda

 

[bimr]

orenda1168,

I would have to disagree. The pool water is highly ozygenated which would surely oxidized practically all the iron to insoluble form.

Chlorine will oxidize iron in 15 minutes at a pH of 5.

How to treat and/or prevent an iron stain: To treat these stains, use a sequestering or chelating agent, which helps hold the iron in solution and create filterable particles.

The recirculating pool filter will eventally remove all of the iron.

http://www.poolspanews.com/2008/032/032qmr_stains.html

 

[orenda1168]

Bimr:

In my twenty-some years of pool water chemistry and treatment, I have yet to see a case in a pool water environment where chlorine as hypochlorus acid (or diatomic oxygen) will oxidize iron compounds to an insoluble state which can then be removed by filtration, any more than Jack Bean's commects about sequestration/chelation producing filterable particles (which is an oxymoron).

The solution with iron, copper and manganese staining is chelation to maintain a water soluble form of the metals and inhibit stain formation.

Orenda

 

[GarySCWSVI]

Dissolved Ferrous Iron and chlorine form Ferric Iron. Done all the time in the Water Treatment Industry. Oxidize the iron with chlorine and then filter it. I have seen many "orange" swimming pool waters. Much of that Ferric Iron ending up on the bottom of the pool.

Gary Schreiber, CWS VI
The Purolite Co.

 

[bimr]

http://www.poolcenter.com/color.htm