Which chlorine/chloramine RO/DI should I buy?

[piranhaman00]

I found the test strips to be plenty accurate enough.

 

[Miami Reef]

I found the test strips to be plenty accurate enough.

The one I got? It says this

It says bromine total chlorine

 

[Randy Holmes-Farley]

You'd want to see zero or close to it for both free chlorine and total chlorine/bromine in the final effluent.

 

[EeyoreIsMySpiritAnimal]

I'd try them on tap water, RO/DI waste water (= water in front of the RO membrane) and on the RO/DI final effluent.

Hasn't the waste water already been through the membrane?
I added a tee/valve to take a sample right after the last carbon, before it hits the membrane at all to make sure I don't have chlorine damaging the membrane.

 

[Randy Holmes-Farley]

Hasn't the waste water already been through the membrane?
I added a tee/valve to take a sample right after the last carbon, before it hits the membrane at all to make sure I don't have chlorine damaging the membrane.

No, wastewater is premembrane.

 

[EeyoreIsMySpiritAnimal]

No, wastewater is premembrane.

Ok, I assumed since the wastewater has significantly higher tds than the tap, it was in contact with the membrane and contained what was removed when the water was filtered.

 

[Miami Reef]

No, wastewater is premembrane.

I always thought wastewater meant the waste of the membrane.

I just call premembrane: water that passed through sediment and carbon filtration.

I found a carbon block on Amazon, but I don’t know if it’s good for my needs. I’m trying to find the share button, but they don’t have it anymore. I need to look harder.

 

[EeyoreIsMySpiritAnimal]

I always thought wastewater meant the waste of the membrane.

I just call premembrane: water that passed through sediment and carbon filtration.

I found a carbon block on Amazon, but I don’t know if it’s good for my needs. I’m trying to find the share button, but they don’t have it anymore. I need to look harder.

I will send you a link to what I order... when I find it, lol

 

[EeyoreIsMySpiritAnimal]

I will send you a link to what I order... when I find it, lol

It's the AquaFX chloramine blaster. I use 2.

 

[Miami Reef]

edit

 

[Randy Holmes-Farley]

Ok, I assumed since the wastewater has significantly higher tds than the tap, it was in contact with the membrane and contained what was removed when the water was filtered.

i think we have a misunderstanding. We are saying the same thing.

To me, premembrane means water on the tap water side of the membrane. That is both water ready to flow through the RO membrane, and wastewater that never does.

Water after passing through the RO membrane would be called postmembrane.

 

[EeyoreIsMySpiritAnimal]

i think we have a misunderstanding. We are saying the same thing.

To me, premembrane means water on the tap water side of the membrane. That is both water ready to flow through the RO membrane, and wastewater that never does.

Water after passing through the RO membrane would be called postmembrane.

Thanks

 

[Miami Reef]

I actually ended up getting the BRS 1 micron chloramine filter instead. Same price, but better IMO.

 

[Malcontent]

I found that two carbon blocks were still inadequate. I was having to change the carbon more often than I liked so I added a third. After I installed a second membrane and booster pump I had to go to 5 carbon blocks.

The recommendation for chloramine removal is a minimum 5 minutes of contact time with GAC.

I used a Hach colorimeter to measure levels that would still be toxic to fish but not detectable by other methods. The limit for DPD methods is 0.02 mg/L but I doubt the color wheel test (which I also have) can go that low since, to the human eye, it looks as crystal clear as the control.

 

[Randy Holmes-Farley]

I found that two carbon blocks were still inadequate. I was having to change the carbon more often than I liked so I added a third. After I installed a second membrane and booster pump I had to go to 5 carbon blocks.

The recommendation for chloramine removal is a minimum 5 minutes of contact time with GAC.

I used a Hach colorimeter to measure levels that would still be toxic to fish but not detectable by other methods. The limit for DPD methods is 0.02 mg/L but I doubt the color wheel test (which I also have) can go that low since, to the human eye, it looks as crystal clear as the control.

But to be fair, if you had 0.02 ppm chloramine in top off water, and added 1% daily top off, the tank would never get over 0.0002 ppm. That sounds like an excessively low level to be concerned with.

 

[Miami Reef]

But to be fair, if you had 0.02 ppm chloramine in top off water, and added 1% daily top off, the tank would never get over 0.0002 ppm. That sounds like an excessively low level to be concerned with.

Won’t it build up over time?

 

[Malcontent]

But to be fair, if you had 0.02 ppm chloramine in top off water, and added 1% daily top off, the tank would never get over 0.0002 ppm. That sounds like an excessively low level to be concerned with.

Well, I often use it for freshwater and do near-total water changes for QT/hospital tanks. I'm not sure what the minimum detection level of chlorine using the color wheel is but I wouldn't be confident it's below 0.05 mg/L. And I wouldn't bet my life that it's below 0.1 mg/L either.

Membrane damage is also a concern although I haven't done the math on that one.

 

[EeyoreIsMySpiritAnimal]

i think we have a misunderstanding. We are saying the same thing.

To me, premembrane means water on the tap water side of the membrane. That is both water ready to flow through the RO membrane, and wastewater that never does.

Water after passing through the RO membrane would be called postmembrane.

But wastewater is what washes the contaminants from the membrane, so doesn't that entail it coming in contact with it?

I'm not trying to be difficult, just wondering if I really need to be taking a water sample prior to the membrane.

 

[Randy Holmes-Farley]

Won’t it build up over time?

I do not think it will accumulate significantly in a reef tank. Too many things to react with. It reacts with bromide to produce other oxidants, not unlike ozone, and like most oxidants, reacts with organics (dissolved, tissues, detritus, etc.)

Table 2 in this article shows the monochloramine half life from reacting 1 ppm with bromide alone in 35 ppt seawater and pH 8 is 8 h.

https://pubs.acs.org/doi/pdf/10.1021/es60165a008

 

[Randy Holmes-Farley]

But wastewater is what washes the contaminants from the membrane, so doesn't that entail it coming in contact with it?

I'm not trying to be difficult, just wondering if I really need to be taking a water sample prior to the membrane.

Yes. This is just a semantic issue. You are just defining the word "premembrane" differently than I am. Neither is, as far as I can tell, clearly right or wrong.

To me, the word premembrane means water just "pre" to the membrane, just before it, touching it, not passing through it. Some of that premembrane water enters the membrane and passes through it (becoming post membrane water), and some of that premembrane water flows away to become the wastewater.

I do not intend the word to mean before it has any interaction with the upstream side of the membrane.

If I wanted to describe water after the sediment and carbon filters, before any interaction with the membrane I'd call that postcarbon filter water, or some such thing.