Removing Tap Water Nitrates with Nitra-Zorb (Experiment Results)

[blyatboy]

UPDATED: Please read the whole post before deciding on this product! It may alter other parameters too.

Hello. I've received a lot of help from @Colin_T and others with my unwell pleco (thread here), so I thought I'd offer up a small contribution to this forum.

As part of this ongoing nightmare, I was struggling to get nitrates down, and found that my tap water measures ~20 PPM by itself.

I dug around, and found a product by API called Nitra-Zorb. It's meant to go in the filter and soak up nitrates for a couple of weeks, then requires recharging in concentrated salty water. There are other nitrate-absorbing resin products too, but this was the one I went with.

I also found an old page from a defunct website (MJV Aquatics) detailing the writer's experience with using to "pre-treat" high nitrate water: https://web.archive.org/web/20210822140717/https://mjvaquatics.com/my-nitrate-fight/

I decided to give it a shot. The pouch came in a few days ago. It took a lot of rinsing to get the dust out first, and the pouch holding the material itself is pretty weak, so I eventually had to replace it.

I filled up a 5 gal bucket of tap water, put the pouch under the intake of a small pump, and let the water circulate:

Did it work? Here are the results. First, the fresh untreated tap water:

After 5 minutes:

After 10 minutes:

And just because I really wanted to get the nitrates down fast, here's what it looked like after 30 minutes:

Hopefully this will help some others in my situation. I'm sure results will vary with the pump used, body of water treated etc. The fella who wrote the article on the MJV website actually took some discontinued tap water filter device from API, and replaced the guts with Nitra-Zorb. Maybe something like that would work faster, but I'm not sure.

All the best

PS: If anyone has any advice, really struggling to help my poor pleco here: https://www.fishforums.net/threads/please-help-my-pleco-mouth-closed-not-breathing-normally.498300/ Thanks in advance.

UPDATE: Just found out that Nitra-Zorb lowered my GH. Your mileage may vary, but I found that while my tap water measures GH 4.0, post Nitra-Zorb it measures GH 3.0.

Turns out the zeolite in the product, designed to remove ammonia, might remove cations like calcium and magnesium from your tap water, and probably replacing them with sodium ions (Na+). This may throw off your parameters and spell trouble for sensitive fish. Especially considering the resin itself is replacing nitrates with chloride ions (which are harmless in itself, especially in the small amounts here).

I remedied this by dumping out the contents of the mesh bag though a sieve, separating the tiny cream-coloured resin spheres from the larger and darker zeolite bits, then put the resin back into my mesh bag.

Results with this resin-only pouch: The same reduction in nitrates, but no decrease in GH.

As a result, for this use case, I would suggest looking for a resin-only product that does not have zeolite in it. I'm still going to keep using this product, but this definitely wasn't ideal for my damaged pleco. All the best.

 

[Colin_T]

That's not bad, 30 minutes to drop the nitrates by 20ppm.
Now we can see if the new nitrate free water helps get the pleco better.

 

[AJ356]

Thanks for this. I'm going to try this product.

 

[GaryE]

Forgive my lack of chemistry knowledge, but do you need to clean or recharge the product to keep it from dumping back?

 

[AJ356]

Forgive my lack of chemistry knowledge, but do you need to clean or recharge the product to keep it from dumping back?

This is what he said Gary

I dug around, and found a product by API called Nitra-Zorb. It's meant to go in the filter and soak up nitrates for a couple of weeks, then requires recharging in concentrated salty water. There are other nitrate-absorbing resin products too, but this was the one I went with.

 

[AJ356]

The product claims to remove ammonia as well, so I am assuming it would only be good for incoming water as part of a water change, because otherwise it might rob the beneficial bacteria of ammonia, do you think?

 

[GaryE]

This is what he said Gary

I dug around, and found a product by API called Nitra-Zorb. It's meant to go in the filter and soak up nitrates for a couple of weeks, then requires recharging in concentrated salty water. There are other nitrate-absorbing resin products too, but this was the one I went with.

I wasn't clear.
A lot of resins were big in the 90s, for various functions, but the issue that made people move away from them (at least in our aquarium club) wasn't that they'd become spent and need recharging, but that they'd release the toxins they were holding as they lost efficiency. Or so it seemed to the non chemists who reported on their success or failure with them.

People would get 'off schedule' with the recharging and find themselves having trouble. Unlike the OP, they weren't dealing with polluted tapwater, but they still had longterm problems.

They could have been blaming toxin dumps when what was happening was waiting too long to recharge though. They were popular with people raising enormous numbers of mbuna.

 

[AJ356]

I wasn't clear.
A lot of resins were big in the 90s, for various functions, but the issue that made people move away from them (at least in our aquarium club) wasn't that they'd become spent and need recharging, but that they'd release the toxins they were holding as they lost efficiency. Or so it seemed to the non chemists who reported on their success or failure with them.

People would get 'off schedule' with the recharging and find themselves having trouble. Unlike the OP, they weren't dealing with polluted tapwater, but they still had longterm problems.

They could have been blaming toxin dumps when what was happening was waiting too long to recharge though. They were popular with people raising enormous numbers of mbuna.

To mitigate this, if the substance that the resins claim to remove is testable (at a reasonable cost), by us testing geeks, then I guess we can just test the "cleaned" water, to see if said substance has been released back into the water, maybe?

 

[gwand]

I used NitroZorb for a few years. My well water has a nitrate concentration of 30 ppm, although recently this has diminished to ~10 ppm. The resin bag is large and only fitted into my Aqua Clear 110 filter box on my 60 gallon tank. I found the resin became saturated with nitrate after 2 weeks and then needed recharging. Two items to note. A new resin bag needs a thorough washing in water devoid of nitrates. This means buying bottled water. Also the resin binds ammonia even better than it binds nitrate. There are actually two resins in the pouch, one binds ammonia and one binds nitrate. Binding all ammonia can be problematic because it theoretically can crash your nitrogen cycle by denying ammonia to the bacteria that metabolizes ammonia into nitrite. So I plumbed a nitrate binding resin filter directly into the sink I perform python mediated water changes. This resin is specific for nitrate and does not dump nitrate when saturated. The filter lasts for about six months and then needs to be replaced.

 

[AJ356]

I used NitroZorb for a few years. My well water has a nitrate concentration of 30 ppm, although recently this has diminished to ~10 ppm. The resin bag is large and only fitted into my Aqua Clear 110 filter box on my 60 gallon tank. I found the resin became saturated with nitrate after 2 weeks and then needed recharging. Two items to note. A new resin bag needs a thorough washing in water devoid of nitrates. This means buying bottled water. Also the resin binds ammonia even better than it binds nitrate. There are actually two resins in the pouch, one binds ammonia and one binds nitrate. Binding all ammonia can be problematic because it theoretically can crash your nitrogen cycle by denying ammonia to the bacteria that metabolizes ammonia into nitrite. So I plumbed a nitrate binding resin filter directly into the sink I perform python mediated water changes. This resin is specific for nitrate and does not dump nitrate when saturated. The filter lasts for about six months and then needs to be replaced.

I think you already told me, but do you mind reminding me of the resin please?

 

[gwand]

I think you already told me, but do you mind reminding me of the resin please?

Aries Filter Works AF-10-3610-BB 4.5'' x 10'' Nitrate Reduction Filter

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www.servapure.com

 

[Colin_T]

They use Zeolite to remove ammonia from water.

The salt water used to recharge the nitrate removing substance can be made from any type of salt but swimming pool salt is the cheapest. Make up a 20 liter bucket of water, add a heap of pool salt, add the nitra-zorb and leave it for a few days. Then rinse under freshwater to remove any salt and away you go.

 

[gwand]

The problem with rechargeable ion exchange resins that use salt, the salt binds to the resin pushing nitrate off from the resin and into the salt water solution. When you put the recharged resin pouch back in the tank, even after copious washings in freshwater, the resin will slowly release salt into the tank water as the resin binds nitrate molecules again. For each molecule of nitrate that binds to the resin, the resin releases, one molecule of sodium chloride.

 

[blyatboy]

The problem with rechargeable ion exchange resins that use salt, the salt binds to the resin pushing nitrate off from the resin and into the salt water solution. When you put the recharged resin pouch back in the tank, even after copious washings in freshwater, the resin will slowly release salt into the tank water as the resin binds nitrate molecules again. For each molecule of nitrate that binds to the resin, the resin releases, one molecule of sodium chloride.

Is this true? My impression was that it released chloride ions, not sodium chloride.

Not gonna lie, I even tasted the treated water just to be sure, just because I was storing the pouch in salt water when not in use. My tongue didn't detect any salt at all...

EDIT: Humbly paging @Essjay as I just came across one of his posts which seems to concur with my understanding: Nitrate and chloride being anions, and sodium being a cation, so nitrate is being absorbed, with chloride ions taking its place.

The product claims to remove ammonia as well, so I am assuming it would only be good for incoming water as part of a water change, because otherwise it might rob the beneficial bacteria of ammonia, do you think?

Yeah, I never intended to put it in my filter at all. Just found out that my tap water was already at 20 PPM of nitrates, and I wanted a way to lower it for water changes.

 

[gwand]

Is this true? My impression was that it released chloride ions, not sodium chloride.

Not gonna lie, I even tasted the treated water just to be sure, just because I was storing the pouch in salt water when not in use. My tongue didn't detect any salt at all...

EDIT: Humbly paging @Essjay as I just came across one of his posts which seems to concur with my understanding: Nitrate and chloride being anions, and sodium being a cation, so nitrate is being absorbed, with chloride ions taking its place.



Yeah, I never intended to put it in my filter at all. Just found out that my tap water was already at 20 PPM of nitrates, and I wanted a way to lower it for water changes.

I stand corrected. You are right. Nitrate is exchanged for chloride.