Tropical Fish Forum

Tropical Fish Keeping Help and Advice => Fishtank Filtration and Cycling => Topic started by: Andy The Minion on November 18, 2016, 08:44:49 PM

Title: Tap water Nitrate removal systems
Post by: Andy The Minion on November 18, 2016, 08:44:49 PM
I saw a link to this page in one of todays advert popups and it interested me (made a change from mail order brides, and anyway, my last one escaped).
Its a resin based water treatment system to reduce Nitrates in domestic water supplies. The design is like a water softener in that it has resin chamber and a salt regeneration cycle.

I cant imagine this being an exchange process, so I was wondering if anybody knew the principle? Is it a reactor or directly capturing the Nitrate?
I have seen fluid bed filters with polymer pellets for Nitrate/Phosphate reduction before, but I thought the media they use was consumed by the process, so maybe its the same but with a much larger tank that needs to be refilled periodically, but then why the salt regen cycle and would a polymer system be acceptable in a potable water system?
Anyhoo it made me wonder if the resin could be used in filters and the regeneration carried out manually like a bag of Purigen.
Title: Re: Tap water Nitrate removal systems
Post by: Sue on November 19, 2016, 09:07:47 AM
Without looking further into it, my instincts say it is an ion exchange resin that swaps nitrate for something else. If it is recharged with common salt (sodium chloride) the ion that exchanges for nitrate has to be chloride.

Seachem says that Purigen
Quote not a mixture of ion exchangers or adsorbents, but a unique macro-porous synthetic polymer that removes soluble and insoluble impurities from water....
so it does not replace one thing with another.
And Seachem, on the Purigen page, says
Watch out for products that claim to be regenerable with a brine solution. That is the regeneration procedure for ion-exchange purposes.
which suggests I'm right about the resin in the ad  ;D

So unlike Purigen, using some of the resin in the ad will remove nitrate but increase chloride in the tank.

But I have no idea how chloride affects fish. My gut reaction is to say that purigen or RO water is the better way to remove nitrate for fish tanks. If RO lowers the hardness by too much you can always add remineralisation salts, and with these you know exactly what you are adding.