Strange icp values of RO

[JonasRoman]

Look at icp of RO. I have always some Si, but these values! Sr, quite high po4, sodium, ca, Mn and sky high Si etc. I have never got anything else than Si. Membrane is 1 year or so. And yes , to be honest, po4 in tank has raised quite much in short time, and also Si, and yes some diatoms on sand. So maybe this was explanation of my increasing po4 after all. In tank its 0.1 now.
I will change membrane and prefilter to be sure but anyway, isn't these values odd that it come so fast? Last icp 6 weeks ago, then only some Si. Can a membrane go bad suddenly??

Jonas

 

[EnterName]

Is this just RO or do you have DI as well?

I mean, most of the elements weren't detectable or low so overall the membrane seems to be holding back a lot, but Si can be hard to get rid of in my experience even with DI.
Sometimes the water digs "tunnels" into the resin and can pass more or less unfiltered through the filter cartridges this way.

Do you happen to have a conductivity meter or TDS meter that is suited for RO/DI testing? I would double check if you get any readings above 0ppm TDS or 1µS/cm conductivity.

 

[JonasRoman]

Is this just RO or do you have DI as well?

I mean, most of the elements weren't detectable or low so overall the membrane seems to be holding back a lot, but Si can be hard to get rid of in my experience even with DI.
Sometimes the water digs "tunnels" into the resin and can pass more or less unfiltered through the filter cartridges this way.

Do you happen to have a conductivity meter or TDS meter that is suited for RO/DI testing? I would double check if you get any readings above 0ppm TDS or 1µS/cm conductivity.

I have DI aswell. Si is always not zero but this time its 50 times higher than I usually have. And I have never had any other ions, always zero on all the others.

I have ordered a new membrane

 

[Randy Holmes-Farley Verified Community Expert]

The strontium is ug/L or mg/L?

 

[EnterName]

The strontium is ug/L or mg/L?

µg/L (stated above "Barium"). The thick red line between Zinc and Aluminum is confusing though, I get it.

 

[Randy Holmes-Farley Verified Community Expert]

Thx, while US tap water can have ppm levels of strontium and so post ro levels could easily be 15 ppb, having that level post di seems unusual.

 

[Jotabe]

Similar situation here ... RO without DI Silicon was 709.3 μg/l (ATI-MS) .. added DI and dropped it to 97.52 μg/l although the DI was somewhat spent (TDS output ~ 8) when those tests were done. With new DI , looking to try an extend the DI life, so installed a 3 way switch between the membrane and the DI .... before re-filling topoff water, bleed off membrane output until TDS drops from ~ 14 to ~3 ...and then switch it into the DI... time will tell if this extends the life of the DI .(Membrane input TDS ~ 90)

 

[JonasRoman]

The strontium is ug/L or mg/L?

ug if I understand FM correct

 

[JonasRoman]

Found reason: cartridge C2 from aqua1900 release po4 and some other stuff(and C2 is mounted after the membrane). Its probably a bad batch of this carbon in C2. Have reported to the manufacturer

 

[EnterName]

Found reason: cartridge C2 from aqua1900 release po4 and some other stuff(and C2 is mounted after the membrane). Its probably a bad batch of this carbon in C2. Have reported to the manufacturer

When buying new membranes they are sometimes coated in some antibacterial stuff. You usually have to flush them without having the water go into your other filters for a while before actual use.
Is it possible you forgot to do this and now C2 is leeching all that weird chemical stuff into the RO/DI over time?

 

[JonasRoman]

When buying new membranes they are sometimes coated in some antibacterial stuff. You usually have to flush them without having the water go into your other filters for a while before actual use.
Is it possible you forgot to do this and now C2 is leeching all that weird chemical stuff into the RO/DI over time?

No. The RO membrane was not new. Only changed C2.

 

[BeanAnimal]

Why are you running a carbon block after the membrane?

 

[EnterName]

Why are you running a carbon block after the membrane?

That's pretty standard in my experience. I have a pre- and post-carbon block as well. It's "the final polish" so to speak (besides the deionization resin).

 

[BeanAnimal]

That's pretty standard in my experience. I have a pre- and post-carbon block as well. It's "the final polish" so to speak (besides the deionization resin).

I don't think it serves any useful purpose for an aquarium. Maybe for drinking water taste, but even then.

Maybe after the rubber bladdered expansion tank before the refrigerator to take away the rubber taste.

 

[EnterName]

I don't think it serves any useful purpose for an aquarium. Maybe for drinking water taste, but even then.

Maybe after the rubber bladdered expansion tank before the refrigerator to take away the rubber taste.

I don't know how big of a difference it makes, but maybe it helps the DI resin to survive for a bit longer which would already be a good reason to have it in my opinion. If it releases something like in Jonas' case, I would certainly also throw it out. It's certainly not essential to the setup.

 

[BeanAnimal]

I don't know how big of a difference it makes, but maybe it helps the DI resin to survive for a bit longer which would already be a good reason to have it in my opinion. If it releases something like in Jonas' case, I would certainly also throw it out. It's certainly not essential to the setup.

That raises a lot of questions (for me at least).

1 - If the carbon is between the RO and the DI resin and leaches something like phosphate, then the resin should handle it. Whatever is not rejected (ignoring volitiles) should be caught by the DI and isn't likely to be caught in the post carbon if it wasn't caught in the pre-carbon.

2 - If the membrane is functioning and the pre filters didn’t catch it, then a post carbon block adds little (anything?) for an aquarium. The pre carbon blocks would have already caught most of the VOCs a post carbon would, and anything left will off gas in the storage tank anyway. That polisher coming after the RO really does nothing it wouldn't do before the RO, and before the RO it offers even more protection for the membrane.

3 - If the carbon block is after the DI, then what purpose does it serve in an aquarium scenario? Drinking water “polishing” to remove the taste from the pressure tank maybe, but even then I question what is really being “polished” even at point of use (potable). And either way we don't typically run drinking water through DI (sure some people do) anyway.

Not being argumentative. I genuinely don't see any benefit and only risk, as demonstrated in Jonas' case. Maybe there is something I am missing.

 

[Randy Holmes-Farley Verified Community Expert]

FWIW, Christoph showed that at least one GAC brand removed some elements but added others.



https://en.oceamo.com/reaktormedien2/

 

[JonasRoman]

Why are you running a carbon block after the membrane?

Because I just followed arquas instructions and could never believe the design was that odd so they added C2 after the RO. Now when I have discovered that I will ofcourse never use that cartridge place for carbon but only use their resin.

 

[JonasRoman]

FWIW, Christoph showed that at least one GAC brand removed some elements but added others.



https://en.oceamo.com/reaktormedien2/

Exact. Thanks for link. Looked at his study and interestingly it showed that Si was added a lot. That was one of the major additions that my C2 added too!. 20 mg/l in the effluent water in my case ! (And as I said 0.2 mg/l Po4).
Arqua is informed.

 

[JonasRoman]

The whole design is ridiculous, as the purpose with a RO equipment is to to remove things, not add. Even if carbon is of high quality it will probably add something. And as we have carbon (C1) prior to RO membrane, the work is already done. And finaly, if carbon seeems to be of poor quality as in my case (C2 from arqua), then it make things very bad.
I can look in the back mirror now and see exactly when my PO4 was raising in my tank, it was immediately after I purchased and added the new C2 (and C1). My Po4 in tank has always been 0.03 ppm ish, after a few weeks using tnis new C2 cartridge my PO4 in tank is 0.12 ppm, AND Si is doubled. Actually I noticed some tendency of dinoflagelates, OR diatoms, on the sand at same time.

I am happy I found the reason quick, as this could have led to something bad.

Arqua says their carbion may release in beginning but not after a while. Its at least in my case not true, my C2 release 0.2 mg/l Po4 still afteer several hundreds of litre production. This batch (hopefully only a batch but who knows) is low quality carbon for sure. But even if next C2 is better I can not know and cannot test the quality every time. So for me, I will never use C2 more for carbon, but use the resin in that place.

Jonas