DIY Ammonia dosing for low nitrate systems

[obanarama]

I just upgraded my one-year-old 75 gallon tank to a 180 gallon two days ago. In the old 75g tank I was dosing very small amounts of ammonium and urea every few days (4MLs~) to keep my Nitrates above 5. Phosphates were around .1 typically without dosing.

Here's the old tank, which was swapped out with the new tank over the course of 24 hours.

You can see some algae on the sand, walls, and rocks.

Here's the new tank as of an hour ago.

The transfer went well with the fish, corals, and rocks placed into totes for the night while we swapped out the tanks. In the new tank I used new Arag-live sand, a couple cups of sand from the old tank, about 30 gallons of water from the old tank, and all of my rocks from the old tank. Everything lived, fish seem totally happy, corals appear to be doing well (tho I've got a Goni that's a little cranky, but its always been a slow extender. )

And the tank looks immaculate.

All of the algae is gone. And today even the algae that was on the rocks and on the snail shells has died and is flaking off. Nitrates went from 4.7 right after the tank swap and are down to .6 now. Phosphates are at .05. Fish all seem very happy.

I'm dosing Microbacter 7 and Seacham stability, fed the corals yesterday afternoon, and I'm feeding pellets and mysis a bit heavy.

Do I dose ammonium and urea to get nitrates up over 5? Or will introducing the ammonium at this early stage of the tank cause issues for the fish? Or should I instead dose straight Nitrate? Or should I just leave things as is and give it a few days and see what happens with the Nitrate numbers?

 

[Evensong]

Probably fine but will reduce alkalinity so you’ll want to account for that.

I think I bought my ammonium carbonate lifetime supply for $9 so it’s not a huge investment. I would bet your phosphate declines when you start dosing ammonia.

Fair point. Something like this, I would assume?

https://a.co/d/bQDz0Mr

And another dumb question: would this also add some carbon to the system?

 

[rishma]

Probably fine but will reduce alkalinity so you’ll want to account for that.

I think I bought my ammonium carbonate lifetime supply for $9 so it’s not a huge investment. I would bet your phosphate declines when you start dosing ammonia.

Fair point. Something like this, I would assume?

https://a.co/d/bQDz0Mr
And another dumb question: would this also add some carbon to the system?

Yes, that is what I bought.

It does not add carbon.

 

[EnterName]

Fair point. Something like this, I would assume?

https://a.co/d/bQDz0Mr
And another dumb question: would this also add some carbon to the system?

Ammonium bicarbonate (NH₄HCO₃) is approx. 77% bicarbonate (HCO₃) by mass. Bicarbonate will provide a bit of alkalinity similar to adding sodium bicarbonate, but as you will be dosing small amounts, it won't be noticeable. (See Edit down below)

Actual "carbon dosing" uses organic carbon sources like ethanol or acetic acid, which heterotrophic bacteria can use as an energy source. Bicarbonates don't work that way, so you don't have to worry about carbon dosing side-effects when adding ammonium bicarbonate. Otherwise you would have the same problem when dosing sodium (bi)carbonate, which is commonly used to provide alkalinity.

Edit: See Randy's explanation down below. Net effect on alkalinity is neutral.

 

[Randy Holmes-Farley Verified Community Expert]

Fair point. Something like this, I would assume?

https://a.co/d/bQDz0Mr

And another dumb question: would this also add some carbon to the system?

That’s exactly what I use. :)

 

[Randy Holmes-Farley Verified Community Expert]

Ammonium bicarbonate (NH₄HCO₃) is approx. 77% bicarbonate (HCO₃) by mass. Bicarbonate will provide a bit of alkalinity similar to adding sodium bicarbonate, but as you will be dosing small amounts, it won't be noticeable.

Actual "carbon dosing" uses organic carbon sources like ethanol or acetic acid, which heterotrophic bacteria can use as an energy source. Bicarbonates don't work that way, so you don't have to worry about carbon dosing side-effects when adding ammonium bicarbonate. Otherwise you would have the same problem when dosing sodium (bi)carbonate, which is commonly used to provide alkalinity.

Ammonia bicarbonate is net alk neutral once the ammonia is consumed. It is a combination of ammonia and CO2, and since both ammonia (once consumed) and CO2 are net alk neutral, the combination is as well. :)

 

[EnterName]

Ammonium bicarbonate (NH₄HCO₃) is approx. 77% bicarbonate (HCO₃) by mass. Bicarbonate will provide a bit of alkalinity similar to adding sodium bicarbonate, but as you will be dosing small amounts, it won't be noticeable.

Actual "carbon dosing" uses organic carbon sources like ethanol or acetic acid, which heterotrophic bacteria can use as an energy source. Bicarbonates don't work that way, so you don't have to worry about carbon dosing side-effects when adding ammonium bicarbonate. Otherwise you would have the same problem when dosing sodium (bi)carbonate, which is commonly used to provide alkalinity.

Ammonia bicarbonate is net alk neutral once the ammonia is consumed. It is a combination of ammonia and CO2, and since both ammonia (once consumed) and CO2 are net alk neutral, the combination is as well. :)

According to one of your articles ammonia assimilation is negative (and nitrate assimilation would be positive, but that's a different story). So once the ammonia is consumed it will counter the effect, but right after dosing it should be slightly positive, shouldn't it?

 

[Randy Holmes-Farley Verified Community Expert]

According to one of your articles ammonia assimilation is negative (and nitrate assimilation would be positive, but that's a different story). So once the ammonia is consumed it will counter the effect, but right after dosing it should be slightly positive, shouldn't it?

Right when dosed ammonia as NH3 will mostly become NH4+, slightly adding alk since it took up H+. Then once metabolized that alk goes away again, unless it becomes nitrate. The ammonia to nitrate conversion consumes alk. If nitrate is stable at any level, then that process is not adding or removing any net alk. Kind of complicated, but unless nitrate is rising or falling a lot, the whole net process of adding and consuming ammonium bicarbonate will be net neutral to alk.

 

[spsick]

Right when dosed ammonia as NH3 will mostly become NH4+, slightly adding alk since it took up H+. Then once metabolized that alk goes away again, unless it becomes nitrate. The ammonia to nitrate conversion consumes alk. If nitrate is stable at any level, then that process is not adding or removing any net alk. Kind of complicated, but unless nitrate is rising or falling a lot, the whole net process of adding and consuming ammonium bicarbonate will be net neutral to alk.

Interesting. I’ve been dosing ammonium bicarbonate again to keep nitrates above 0.0 and again noticing a disproportionate alk drop. Calcium, magnesium, and phosphate staying stable which indicate I don’t have increased consumption.

 

[Randy Holmes-Farley Verified Community Expert]

Interesting. I’ve been dosing ammonium bicarbonate again to keep nitrates above 0.0 and again noticing a disproportionate alk drop. Calcium, magnesium, and phosphate staying stable which indicate I don’t have increased consumption.

While I do not know what exactly caused your observation, a drop of 1 dKH by increased calcification would not be accompanied by a calcium drop that is reliably detectable with most kits (~7 ppm). Also, a rise in nitrate will deplete alk. 2.3 dKH per 50 ppm nitrate increase.

 

[spsick]

While I do not know what exactly caused your observation, a drop of 1 dKH by increased calcification would not be accompanied by a calcium drop that is reliably detectable with most kits (~7 ppm). Also, a rise in nitrate will deplete alk. 2.3 dKH per 50 ppm nitrate increase.

Ah shoot thanks Randy, that’s the piece I was missing. The ongoing nitrate rise depleting it.

I swear you have an answer for every mystery!!

 

[buruskeee]

Fair point. Something like this, I would assume?

https://a.co/d/bQDz0Mr

And another dumb question: would this also add some carbon to the system?

That’s exactly what I use but mix it a little less potent. I make sure my 1L of solution dumped into my 150g will never equate to more than 0.4ppm ammonia if accidentally dumped in. I believe I’m doing 12g into 1L and I dose 30ml a day to stay around 3-5ppm nitrate.

Good thing about dosing ammonia is there’s less of a chance to starve since nitrate is the end result. When dosing nitrates, it still has to convert back to ammonia so you never know if the resulting nitrate is not being used or still being converted.

 

[EnterName]

Fair point. Something like this, I would assume?

https://a.co/d/bQDz0Mr

And another dumb question: would this also add some carbon to the system?

That’s exactly what I use but mix it a little less potent. I make sure my 1L of solution dumped into my 150g will never equate to more than 0.4ppm ammonia if accidentally dumped in. I believe I’m doing 12g into 1L and I dose 30ml a day to stay around 3-5ppm nitrate.

Good thing about dosing ammonia is there’s less of a chance to starve since nitrate is the end result. When dosing nitrates, it still has to convert back to ammonia so you never know if the resulting nitrate is not being used or still being converted.

Did the math so you don't have to :D

12g/L ammonium bicarbonate is approx. 0.1518mol/L ammonium or 2.74g/L NH4 = 2740ppm NH4.

0.001L = 1mL of that solution contains 2.74mg NH4 and spread over 100L it would result in 0.0274ppm NH4 or approx. 0.005ppm NH4 in your 150gal.

If you are adding 30mL that's approx. 0.82ppm NH4 in 100L or 0.14ppm NH4 in your 150gal.

If you were to accidentally dose the whole 1L bottle it would cause a spike of 4.8ppm NH4 (≈ 2740mg/L • 1L / 568L). In other words: Dosing the whole bottle would be less than 0.4ppm unionized ammonia, but around 4.8ppm total ammonia.

The actual toxicity of such levels is often misunderstood: https://www.reef2reef.com/ams/ammonia-is-our-friend.1062/

 

[buruskeee]

Did the math so you don't have to :D

If you were to accidentally dose the whole 1L bottle it would cause a spike of 4.8ppm NH4 (≈ 2740mg/L • 1L / 568L). In other words: Dosing the whole bottle would be less than 0.4ppm unionized ammonia, but around 4.8ppm total ammonia.

The actual toxicity of such levels is often misunderstood: https://www.reef2reef.com/ams/ammonia-is-our-friend.1062/

That’s the 0.4ppm number I was referring to. So, even though it’s misunderstood, are we in the clear, or is this bad? lol. Thankfully my DOS has been working perfectly for the last year I’ve been dosing it.

Whether it be unionized or total ammonia, do we know what the upper threshold of concentration is that is just below stressful to fish?

I remember seeing somewhere about different species and their lethal concentration like Tangs etc, but can’t remember where. That RFH thread has like random fish groups of fresh water and saltwater.

 

[EnterName]

Did the math so you don't have to :D

If you were to accidentally dose the whole 1L bottle it would cause a spike of 4.8ppm NH4 (≈ 2740mg/L • 1L / 568L). In other words: Dosing the whole bottle would be less than 0.4ppm unionized ammonia, but around 4.8ppm total ammonia.

The actual toxicity of such levels is often misunderstood: https://www.reef2reef.com/ams/ammonia-is-our-friend.1062/

That’s the 0.4ppm number I was referring to. So, even though it’s misunderstood, are we in the clear, or is this bad? lol. Thankfully my DOS has been working perfectly for the last year I’ve been dosing it.

Whether it be unionized or total ammonia, do we know what the upper threshold of concentration is that is just below stressful to fish?

I remember seeing somewhere about different species and their lethal concentration like Tangs etc, but can’t remember where. That RFH thread has like random fish groups of fresh water and saltwater.

[Reply was posted twice, see below]

 

[EnterName]

Did the math so you don't have to :D

If you were to accidentally dose the whole 1L bottle it would cause a spike of 4.8ppm NH4 (≈ 2740mg/L • 1L / 568L). In other words: Dosing the whole bottle would be less than 0.4ppm unionized ammonia, but around 4.8ppm total ammonia.

The actual toxicity of such levels is often misunderstood: https://www.reef2reef.com/ams/ammonia-is-our-friend.1062/

That’s the 0.4ppm number I was referring to. So, even though it’s misunderstood, are we in the clear, or is this bad? lol. Thankfully my DOS has been working perfectly for the last year I’ve been dosing it.

Whether it be unionized or total ammonia, do we know what the upper threshold of concentration is that is just below stressful to fish?

I remember seeing somewhere about different species and their lethal concentration like Tangs etc, but can’t remember where. That RFH thread has like random fish groups of fresh water and saltwater.

To cite Randy on this topic:

"Concentrations of ammonia that are not acutely lethal can still cause significant problems for fish. Salmon in seawater at pH 7.8, for example, [...] were more prone to disease, when exposed to sublethal concentrations of ammonia. Consequently, aquarists should strive to keep ammonia concentrations well below lethal levels."

"My suggestion is to take some sort of corrective action if the total ammonia rises above 0.1 ppm. [...]. Values in excess of 0.25 ppm total ammonia may require immediate treatment, [...]."

Source: http://reefkeeping.com/issues/2007-02/rhf/index.php (if that page doesn't load https://web.archive.org/web/20241228064856/http://reefkeeping.com/issues/2007-02/rhf/index.php)

Summarizing: Will something die immediately? Probably not, the time of exposure plays a huge role. Does it still affect the health of your fish and other reef inhabitants? Possibly, and it might make them prone to illness.

I think there is a good reason why Randy is still careful about suggesting adding more than 0.1ppm total ammonia at once. You would be adding far more total ammonia in this "worst case".

 

[Randy Holmes-Farley Verified Community Expert]

Depending on the speed of the delivery, adding 4.8 ppm total ammonia is not something I'd want to do. But if the pump is slow enough that even stuck on and delivering the whole bottle takes a large portion of a day, it is less of a risk.

My dosing rate and container is nearly the same, with dumping the whole bottle delivering around 4 ppm, but I have not been overly worried about that. I use a BRS 1.1 mL per min dosing pump on a simple electronic timer.

 

[buruskeee]

Depending on the speed of the delivery, adding 4.8 ppm total ammonia is not something I'd want to do. But if the pump is slow enough that even stuck on and delivering the whole bottle takes a large portion of a day, it is less of a risk.

My dosing rate and container is nearly the same, with dumping the whole bottle delivering around 4 ppm, but I have not been overly worried about that. I use a BRS 1.1 mL per min dosing pump on a simple electronic timer.

I’m mostly concerned with the whole 1L being dosed on accident. My DOS is set to dosing my 30ml (0.14ppm in 150g) over my lighting period for 6 hours (0.2ppm per hour). My DOS has the ability to dose 250ml per hour (1.2ppm per hour in 150g).

Should I get a less capable dosing head to dose NH4?

 

[Randy Holmes-Farley Verified Community Expert]

I’m mostly concerned with the whole 1L being dosed on accident. My DOS is set to dosing my 30ml (0.14ppm in 150g) over my lighting period for 6 hours (0.2ppm per hour). My DOS has the ability to dose 250ml per hour (1.2ppm per hour in 150g).

Should I get a less capable dosing head to dose NH4?

You could just dilute it to a level you are comfortable with.

 

[buruskeee]

You could just dilute it to a level you are comfortable with.

What’s a non-lethal total ammonia level for typical reef fish that aren’t salmon? 2ppm?