Purolite 502E question.

[steve b]

Re: Purolite 502E question.

Dear colleagues,
These kind of Purolite adsorbents are strong anion exchangers. They are not specific, but selective, which means they do not only remove the main target (NO3-), but also other anions. These are SO4--, Cl-, HCO3-, and even PO4---, among others. These adsorbents exchange the mentioned anions with Cl-. Thats why they are intended to be regenerated with NaCl: Na+ will pass the sorbent during regeneration, Cl- will be exchange by NO3- (and other anions) -> NaNO3 (in solution) is flushed out of the sorbent during regeneration (as well as Na2SO4, NaCl, etc.).
If you use NaOH for regeneration, OH- instead of Cl- will be realeased into the tank which will 1) raise the pH in your tank and 2) lead to an asymmetry between H+ and OH- and access OH- will raise the conductivity AND THE pH! Thats not what you intend, is it?

Since also HCO3- is exchanged, it is clear that you register a drop in KH.

You should keep in mind that the use of nitrate sorbents "contaminate" your tank with Cl-, which is just the lesser evil than nitrate. Dont forget about the regular water exchange in order to reduce the Cl- concentration
and to keep your water as natural as possible.


Recommended reading:
T. Nur, M.A.H. Johir, P. Loganathan, S. Vigneswaran, J. Kandasamy: Effectiveness of purolite A500PS and A520E ion exchange resins on the removal of nitrate and phosphate from synthetic water. Journal: Desalination and Water Treatment. 47 (2012) 50–58 (Sept).

Regards,
Jens (working with adsorption in biomedicine for 25 years)

That's great info, thanks and nice to have your experience on the Forum and welcome.

[Tschens]

Re: Purolite 502E question.

Thanks a lot for the warm welcome! To avoid off-topic discussions in this thread, I introduced myself here:

https://forum.simplydiscus.com/showthread.php?141054-Malawi-Friend-diver-and-biologist

[steve b]

Re: Purolite 502E question.

Reading the above again I have been thinking that replacing No3 with CL might be the cause of my 1st Ram fish deaths? I mix 20l of Di with 5l of Purolite A-520E Nitrate Removal Resin water. I get 0ppm of Nitrate to mix to my Di water. My tap water is 30ppm No3 that's why I am using the Purolite.
Has anyone who uses this had problems? My Sterbai and BN are doing fine in the water that the Rams died in. If this is the case I might have to use powder to re min.

[steve b]

Okay it has been 2 weeks now with 2 new pairs of Rams and both doing fine. 1 pair in bare bottom tank and the other in the 5' planted tank, the one where I lost my 1st Rams. The only change I have made is NOT to filter through the Purolite resin. Now I re gen with Equilibrium (Gh) and Potassium BiCarbonate (Kh) So the only conclusion I can come to is that the Rams were harmed by the Chloride in the water changes and build up of Chloride +100ppm when tested as the W/C water had Chloride in it each time.

[steve b]

Been a while since I posted this thread.
I have been using RO waste water to re min my w/c water, the waste water has a No3 of about 30ppm
I did pass it through Purolite 502E but the Nitrate was replaced by Chloride.
Still trying to lower my tank No3 but still adding it at w/c.
I wondered if I pass the output of the Purolite 502E water through a Carbon block filter that removes Chlorine/Chlorimine, would it also remove the Chloride? giving me remin water with no No3 and no Cl.

[steve b]

Done a bit more reading and looks like a Carbon filter will not remove the Chloride salt from my w/c water. Must find another way.

[steve b]

Done some more testing and found my waste water has approx 100ppm of Chloride and the water through the Purlite resin has also around 100ppm Chloride. So am I worrying about nothing? The waste has 30ppm of Nitrate and the Resin has 0 Nitrate.


Nitrate test 0 & 30ppm The top strip test is RO 0ppm Chloride, Middle and Bottom, Waste water and Resin water around 100ppm Chloride.

I could go the powder remix to RO but that's a lot of wasted water when it could be used.

[steve b]

So I sent some emails and got a few back.
One was saying that the very little Chloride added is like adding a little aquarium salt to the tank.
Another from Mark at Devotedly Discus (UK) Said they used it for 15 years and never had a problem with their Discus.

So looks like Chloride had no effect on the health of the Rams I bought and they died of other causes.
So going to use it to remind and see.