Purolite 502E question.

[steve b]

Hi All, been testing my waters for my new set up.

Passing my tap water through Purolite 502E Nitrate removal resin and having some strange readings. If anyone uses this may know what's happening.

Tap water is ph 7.6 TDS 350 Kh 9 NO3 30ppm
Purolite 502E ph 6.8 TDS 420 Kh 3 NO3 0ppm

Drop in Ph, slight increase in TDS and large drop in Kh.

Will be adding this to remin my RO/DI for tanks.

[brewmaster15]

Steve, I dont use that but 2 questions... do you have to pretreat that resin? And is it an ion exchange resin?

[steve b]

Steve, I dont use that but 2 questions... do you have to pretreat that resin? And is it an ion exchange resin?

No pre treatment just wash and I believe it's an Anion resin, there seems to be some chemistry going on. Water looks good to use but just want to make sure before I start the fish going in. Might be worth while emailing Purolite direct.

nb just sent a note to Purolite.

[steve b]

Just an update. After aeration for 24hrs the PH back to tap parameters PH 7.6, Kh remains the same at Kh3

[brewmaster15]

Steve any idea where the increase in TDS came from?

[steve b]

Steve any idea where the increase in TDS came from?

Not sure, hope Purolite have some answers. Maybe the Calcium is being replaced with Sodium and that pushes up TDS?


Done a test with mixing the water 3:1 and get 120TDS 7Ph with 1Kh. Any idea how to increase Kh without increasing TDS or Ph... (don't think so). need to get water around 50 TDS 6.8Ph

[brewmaster15]

The only way I can think in your case is to strip the water down to almost nothing with a R/O coupled to DI.
. Then add a kH buffer .. it will also add tds but net result should be higher KH and a lower TDS. Im not sure how much TDS you will add back as thats going to depend on the buffer and is trial and error..

Hope that makes sense.

Incidentally if you use the RoDI you probably will not even need to worry about those Nitrate levels and using the 502 E resin.

[steve b]

Thanks, that will work as you say Trial & Error! I will keep everyone posted to what I end up with.

[Snug]

Interesting. I just ordered Purolite A520E. The drop in dKH must be the resin replacing carbonate with chloride which I think A520E comes preloaded with. I planned to use the A520E directly in my aquarium to remove nitrates.

If you regenerate A520E with caustic soda instead of table salt, the nitrate will be replaced with hydroxide instead of chloride which doesn't contribute to tds.

[steve b]

If you regenerate A520E with caustic soda instead of table salt, the nitrate will be replaced with hydroxide instead of chloride which doesn't contribute to tds.

Didn't know you could do it both ways thought it was only salt?