Caution with food grade NaOH

[Formulator]

My most recent ICP test showed extremely elevated lithium (1120 ug/L) and by process of elimination and some mathematical feasibility calculations, I’ve come to suspect my NaOH as the culprit.

After some research, it seems food grade regulations don’t include any specification for lithium as an impurity and it may be present at trace levels in NaOH if it was derived from natural brines high in lithium (common in western US, South America, and China). I dose about 110 mL of Randy’s high pH boost recipe per day, or about 8.2 g NaOH per day to a 130 g system. This means that to reach my current lithium level over the course of 6 months, my NaOH source would only need to contain about 28 ppm lithium; well within the realm of possibility for an unregulated impurity.

In general I wonder if we should revisit our use of food grade chemicals in the hobby for supplements used in high volumes such as Alk and Calcium in med-high demand systems. For impurities like Li with no natural export pathway, even trace impurities can build up to meaningful levels over time. This is especially true in systems operating under a no-water-change dogma like mine.

The particular brand in question here is this one from Belle Chemical I found on Amazon. I may try getting some ICP testing done to confirm my hypothesis, if I can find a lab to do it.

I think I will be switching to an ACS reagent grade source, regardless.

 

[DaJMasta]

Do you mean parts per billion? Parts per million would put you in the 1ppt of lithium in your water, which i presume would kill everything outright.

If it is 1100ppb (1ppm) and it's an OES ICP test, you're really only starting to get into a reasonable measurement range and I would try another test. Are you seeing any issues in your livestock?

 

[Formulator]

Do you mean parts per billion? Parts per million would put you in the 1ppt of lithium in your water, which i presume would kill everything outright.

If it is 1100ppb (1ppm) and it's an OES ICP test, you're really only starting to get into a reasonable measurement range and I would try another test. Are you seeing any issues in your livestock?

Yes, good catch. It is 1100 ug/L = 1.1 ppm. It is ICP-MS, not OES, and I have been testing consistently over the course of a year with an obvious upward trend after switching from bicarbonate to NaOH for alk. No livestock issues (yet).

 

[Reefering1]

How are you so confident it's that? I would think it would be heard of by now. Which exact product did you use?

 

[Formulator]

How are you so confident it's that? I would think it would be heard of by now. Which exact product did you use?

I’m not 100% confident. In my original post I said “I suspect” and “I may send for ICP to confirm my hypothesis if I can find a lab”. I also provided the brand I was using and a photo of its label.

 

[Reefering1]

I’m not 100% confident. In my original post I said “I suspect” and “I may send for ICP to confirm my hypothesis if I can find a lab”. I also provided the brand I was using and a photo of its label.

I'll rephrase my question...

How confident are you that there were no other changes in input, equipment, meds, supplements or contamination? No changes in brand of food, or even between packages?

I understand you're not sure, and that it is entirely possible- just wondering how much thought went into everything else that could be possible.
Just seems like more people would be having issues, you're the 1st ive read. Iirc, that's the same product randy recommends(?)
Like you said, only a lab can definitively prove anything. Just pondering

 

[Randy Holmes-Farley Verified Community Expert]

@Miami Reef is using NaOH and I think got an icp. :)

 

[Miami Reef]

I use that same brand of NaOH. I dose gallons and gallons of that in my 260 gallon tank, and I haven’t changed any water since October 2024.


Here are my ICPs spanning almost a year.

I also started dosing Tropic Marin A- since last year, which actively contains lithium. I’m dosing a lot of it, and I still don’t have elevated lithium.

 

[Reefering1]

I use that same brand of NaOH. I dose gallons and gallons of that in my 260 gallon tank, and I haven’t changed any water since October 2024.


Here are my ICPs spanning almost a year.

I also started dosing Tropic Marin A- since last year, which actively contains lithium. I’m dosing a lot of it, and I still don’t have elevated lithium.

How long have you been using that same specific NaOH product?

 

[Miami Reef]

How long have you been using that same specific NaOH product?

Several years. I started in 2022. I always used this same brand from Amazon.

Here it is:

They very recently (few months ago) started wrapping the entire bottles with plastic. I’ve been using it for the long haul. :)

 

[Formulator]

I use that same brand of NaOH. I dose gallons and gallons of that in my 260 gallon tank, and I haven’t changed any water since October 2024.


Here are my ICPs spanning almost a year.

I also started dosing Tropic Marin A- since last year, which actively contains lithium. I’m dosing a lot of it, and I still don’t have elevated lithium.

Well, that settles it in my mind. Not the NaOH.

Other potential culprits:

• Lab grade sodium silicate solution but the dose is very small so I tend to doubt it.
• Food grade Calcium Chloride
• Reef moonshiners elements
• Brightwell neonitro
• Leachables from plastics or acrylic (I’m suspicious of the acrylic Neptune apex cylindrical dosing containers and their compatibility with my NaOH solution. Probably should be using HDPE.)

 

[Miami Reef]

I don’t think it’s Moonshiners because we’d see much more reports of this. Their system requires managing elements and frequent testing.

What salt mix did you start with? Was the lithium always this high with ICP?

Lithium has a low toxicity profile, so I’m not overly concerned.

 

[Formulator]

I don’t think it’s Moonshiners because we’d see much more reports of this. Their system requires managing elements and frequent testing.

What salt mix did you start with? Was the lithium always this high with ICP?

Lithium has a low toxicity profile, so I’m not overly concerned.

I doubt it is the moonshiners also. I have always used reef crystals salt. It has been elevated in the last year but climbed from 500 to 700 to 1100 ug/L over the course of the last 8 months.

I’m also not overly concerned but if it is in one of my regularly dosed solutions I want to fix that before it does inevitably rise to toxic levels.

 

[Formulator]

I'll rephrase my question...

How confident are you that there were no other changes in input, equipment, meds, supplements or contamination? No changes in brand of food, or even between packages?

I understand you're not sure, and that it is entirely possible- just wondering how much thought went into everything else that could be possible.
Just seems like more people would be having issues, you're the 1st ive read. Iirc, that's the same product randy recommends(?)
Like you said, only a lab can definitively prove anything. Just pondering

It seems you were right to question! Based on miami’s experience it must be something else. I listed my other dosing solutions in my earlier response if you have any ideas.

 

[bp908]

Adding another data point - I've been using the same Belle Chemical NAOH since June 2024 with no major water changes in that time in my 140g system. Latest ICP is below, which shows moderately elevated lithium levels, but has been between 250-290 ug/l since I've started dosing this, with no trend.

I use NAOH for about 1/2 of my alkalinity supplementation - on average that's around 1.5-2 DKH per day (higher now, lower when starting). The other half is sodium bicarbonate.

 

[RelaxingWithTheReef]

Since my trace elements are seemingly under control, and being super busy, I have not been keeping up with water changes. Tanks look great, but Lithium levels are going up. Needless to say, I need to get up to date with water changes.

New Blue Bucket salt = 205 ug/L Lithium

The 5 gal tank uses 4 dKH/day B-Ionic 2-part, I feed LRS Reef Frenzy, and add 0.020 ppm NeoPhos/day:

5/17/24 with weekly water changes = 486 ug/L
8/7/24 with 4 water changes = 848 ug/L
10/7/24 with 0 water changes = 1422 ug/L

I have only performed 3 water changes since, and I’m afraid to learn what the current Lithium level is. Probably over 2000 ug/L.


My SPS uses 2 dKH/day B-Ionic 2-part, and I feed LRS Reef Frenzy:
With water changes the tank measures around 300 ug/L.
Without significant water changes since July 2024, this Tank is also climbing. It was at 780 ug/L on the last test 12/2/24.

The only sources I can think of are B-Ionic two part, Reef Frenzy, or some things leaching. I’m leaning towards B-Ionic, but the source remains a mystery at this point.

 

[Formulator]

Since my trace elements are seemingly under control, and being super busy, I have not been keeping up with water changes. Tanks look great, but Lithium levels are going up. Needless to say, I need to get up to date with water changes.

New Blue Bucket salt = 205 ug/L Lithium

The 5 gal tank uses 4 dKH/day B-Ionic 2-part, I feed LRS Reef Frenzy, and add 0.020 ppm NeoPhos/day:

5/17/24 with weekly water changes = 486 ug/L
8/7/24 with 4 water changes = 848 ug/L
10/7/24 with 0 water changes = 1422 ug/L

I have only performed 3 water changes since, and I’m afraid to learn what the current Lithium level is. Probably over 2000 ug/L.


My SPS uses 2 dKH/day B-Ionic 2-part, and I feed LRS Reef Frenzy:
With water changes the tank measures around 300 ug/L.
Without significant water changes since July 2024, this Tank is also climbing. It was at 780 ug/L on the last test 12/2/24.

The only sources I can think of are B-Ionic two part, Reef Frenzy, or some things leaching. I’m leaning towards B-Ionic, but the source remains a mystery at this point.

One thing in common between you and I would be the brightwell NeoX. Though I use NeoNitro daily and you are using NeoPhos. Probably a meaningless coincidence, but worth noting.

 

[Reefering1]

It seems you were right to question! Based on miami’s experience it must be something else. I listed my other dosing solutions in my earlier response if you have any ideas.

In my simple mind, in this case, a ounce of cure might be worth a pound of diagnosing. I would probably slap a couple polyfilters in, change nothing else, and check again in a month or 2. This is assuming the corals look good and in no immediate danger.

 

[LobsterOfJustice]

Jumping in on this conversation a few months late. My Lithium levels have been steadily rising despite regular maintenance water changes performed with IO salt (confirmed via second ICP provider). Like the OP, I also use DIY food grade additives for NaOH, Calcium Chloride, and Arm & Hammer baking soda. The only other notable thing is that I introduce an extremely high amount of new frag plugs in this system - around 200 per month. I soak them in water before use but I'm not convinced they're completely cured/inert by the time I use them.

To be clear, I'm not seeing any issues in the tank, and I'm not freaking out over this. Just trying to be a little proactive on an atypical result.

 

[Randy Holmes-Farley Verified Community Expert]

What lithium level?