alkalinity dosing - soda ash or sodium bicarbonate

[reef tank 2.0]

looks like im gonna have to start dosing here before long...I want my numbers slightly higher, i think.

when it comes to alkalinity - BRS had a video about dosing. they mention that you should use sodium bicarbonate to get the parameter up (big swing), then use soda ash for your daily top offs.

if i need to increase my alkalinity by 2-3dkh, can that be done with soda ash, or do I need the bicarbonate? what's considered a LARGE swing? i know soda ash can increase ph, which is my concern.

 

[Savage Henry]

I’m really just following, but will jump in before more informed hobbyist give you better advice.

Both bicarb and carb will increase KH. Just be careful about how rapidly you increase KH. You say you want to increase KH by 3. You’ll need to do this over some days. Either will get you there.

I add solid sodium carbonate (carb).

Read up as you do need to be careful how you add carb if you are also adding calcium. I add calcium chloride. I did have an issue where I added the carb and the calcium chloride too close and I got calcium carbonate precipitating everywhere and it caused my return pump to fail (in between pauses) because the precipitate formed in the pump.

 

[Savage Henry]

Also, as long as you don’t add the KH increases too quickly, don’t worry about the pH. The KH will take care of that. The KH is a measure of the capacity of the water to buffer changed in ph. It sort of acts like a sponge in mopping up both too much high pH (hydroxide ion) and too much low pH (hydride??? -H ions). So, if you carefully raise your KH to an acceptable level, your pH will be OK.

 

[Randy Holmes-Farley Verified Community Expert]

pH raising us almost always a benefit, not a detriment.

There are many ways to supplement alkalinity, and I’d suggest at this stage that Tropic Marin AFR might be a good choice.

But sodium bicarbonate and carbonate are also good choices, as is sodium hydroxide if you want an even bigger pH boost.

 

[Savage Henry]

One difference between using bicarbonate, carbonate and sodium hydroxide is how high you can accidentally raise pH. Sodium hydroxide is extremely risky. Also, sodium hydroxide will not raise your KH as it does not added any buffering capacity.

 

[KStatefan]

looks like im gonna have to start dosing here before long...I want my numbers slightly higher, i think.

when it comes to alkalinity - BRS had a video about dosing. they mention that you should use sodium bicarbonate to get the parameter up (big swing), then use soda ash for your daily top offs.

if i need to increase my alkalinity by 2-3dkh, can that be done with soda ash, or do I need the bicarbonate? what's considered a LARGE swing? i know soda ash can increase ph, which is my concern.

I think a baking soda solution is the best for making adjustment to you alkalinity. I make changes slowly of 0.5 dkh per day. Lots of options for maintenance dosing.

 

[KStatefan]

One difference between using bicarbonate, carbonate and sodium hydroxide is how high you can accidentally raise pH. Sodium hydroxide is extremely risky. Also, sodium hydroxide will not raise your KH as it does not added any buffering capacity.

Sodium Hydroxide will raise dKH. You can make a solution that matches Soda Ash solution.

 

[Randy Holmes-Farley Verified Community Expert]

One difference between using bicarbonate, carbonate and sodium hydroxide is how high you can accidentally raise pH. Sodium hydroxide is extremely risky. Also, sodium hydroxide will not raise your KH as it does not added any buffering capacity.

Sodium hydroxide is a perfectly suitable alkalinity additive. Reefers have used hydroxide for decades. It’s all I used for 20 years.

 

[Randy Holmes-Farley Verified Community Expert]

This section from one of my kalkwasser articles explains the hydroxide usage:

The calcium ions in the solution obviously supply calcium to the aquarium, and the hydroxide ions supply alkalinity. Hydroxide itself provides alkalinity (both by definition and as measured with an alkalinity test), but corals consume alkalinity as bicarbonate, not hydroxide. Fortunately, when limewater is used in a reef aquarium, it quickly combines with atmospheric and dissolved carbon dioxide and bicarbonate to form bicarbonate and carbonate:

4. OH- + CO2 —> HCO3-
5. OH- + HCO3- —> CO3-- + H2O

In an aquarium with an acceptable pH, there is no concern that the alkalinity provided by limewater is any different from any other carbonate alkalinity supplement. The hydroxide immediately disappears into the bicarbonate/carbonate system. In other words, the amount of hydroxide present in aquarium water is really a function of only pH (regardless of what has been added), and at any pH below 9, it is an insignificant factor in alkalinity tests (much less than 0.1 meq/L). Consequently, the fact that alkalinity is initially supplied as hydroxide is not to be viewed as problematic, except as it impacts pH (see below).

 

[Savage Henry]

OK, but hydroxide doesn’t provide any buffering capacity. Use it to eliminate acid for sure.

 

[Randy Holmes-Farley Verified Community Expert]

OK, but hydroxide doesn’t provide any buffering capacity. Use it to eliminate acid for sure.

That is a misleading statement. I think you may not fully understand the chemistry of hydroxide added to seawater.

Different people can mean different things by “buffering capacity”, but dosing hydroxide instantly

1. Increases the total and carbonate alkalinity as measured by any test method reefers use

2. Increases the concentration of carbonate by reacting with bicarbonate.

3. Increases the literal chemical property called “buffering capacity”. That is, the water is more resistant to upward or downward pH swings. That is due to the increased carbonate, which provides the buffering as half of the bicarbonate/carbonate buffer pair. The increased carbonate and decreased bicarbonate is a better buffer with more carbonate because at any normal reef tank pH, the carbonate half of the buffer is in short supply.

Over time (minutes to hours) a tank dosed with hydroxide will pull in CO2 from the air. That CO2 mostly reacts with the carbonate that was boosted to make more bicarbonate. Thus, in the end, both bicarbonate and carbonate rise, leaving only a tiny bit more hydroxide than was there before dosing.

 

[reef tank 2.0]

im really nervous about dosing. did it on my first tank had and that was a disaster.
trying to avoid that headache. I've been watching BRS videos on it and I hear a lot about the ph increasing when using dry soda ash which is why it's best to add at night after lights out.

I could try a really small amount and test daily to see how it goes. test both alkalinity and calcium.
I will try manually dosing first, then if all goes well, I will use my BRS dosers.

I have pouches of soda ash and calcium chloride sitting on the shelf from my first tank many moons ago (years), so as long as there isn't a shelf life, I should be good to go.

 

[Randy Holmes-Farley Verified Community Expert]

im really nervous about dosing. did it on my first tank had and that was a disaster.
trying to avoid that headache. I've been watching BRS videos on it and I hear a lot about the ph increasing when using dry soda ash which is why it's best to add at night after lights out.

I could try a really small amount and test daily to see how it goes. test both alkalinity and calcium.
I will try manually dosing first, then if all goes well, I will use my BRS dosers.

I have pouches of soda ash and calcium chloride sitting on the shelf from my first tank many moons ago (years), so as long as there isn't a shelf life, I should be good to go.

Soda ash dosing is not going to be any sort of pH problem. No one should worry about that when starting off dosing, which always involves small amounts.

That said, there’s no reason for a new reefer with a new tank to not just pick All For Reef from Tropic Marin , unless cost is the major priority. It’s an easy to dose all in one product that you can manually dose.

 

[reef tank 2.0]

I saw you mentioned that Tropic Marin in earlier posts. :)
I will look into that.

details are fuzzy, but I remember last time when I dosed soda ash, my ALK never changed. no matter how much dosed. I recall calcium skyrocketing and I had calcium deposits everywhere. I recall huge hard clumps of sand and hard sheets of calcium in my sump. if recall right. I know this was all operator error. but either way, first go round left a bad taste in my mouth.

thanks for the help.

I didn't see all these posts till now.

 

[Savage Henry]

That is a misleading statement. I think you may not fully understand the chemistry of hydroxide added to seawater.

Different people can mean different things by “buffering capacity”, but dosing hydroxide instantly

1. Increases the total and carbonate alkalinity as measured by any test method reefers use

2. Increases the concentration of carbonate by reacting with bicarbonate.

3. Increases the literal chemical property called “buffering capacity”. That is, the water is more resistant to upward or downward pH swings. That is due to the increased carbonate, which provides the buffering as half of the bicarbonate/carbonate buffer pair. The increased carbonate and decreased bicarbonate is a better buffer with more carbonate because at any normal reef tank pH, the carbonate half of the buffer is in short supply.

Over time (minutes to hours) a tank dosed with hydroxide will pull in CO2 from the air. That CO2 mostly reacts with the carbonate that was boosted to make more bicarbonate. Thus, in the end, both bicarbonate and carbonate rise, leaving only a tiny bit more hydroxide than was there before dosing.

Yes, I do recall having to seal our bottles of sodium hydroxide in the lab due to carbonates forming from absorption of carbon dioxide and yes you never kept sodium hydroxide as a standard solution unless you were prepared to standardise it before every use. And so in that respect sodium hydroxide can be used to prepare carbonate buffer, particularly if your tank absorbs carbon dioxide. Though sodium hydroxide of itself has no buffering capacity in the sense of carbonate i.e. for carbonate hardness.

 

[reef tank 2.0]

i have a question about that All For Reef stuff. for the all in one mixture. (that isn't as expensive as I was guessing it would be)

if that all in one mixture has all the elements combined..do you first need to get all your parameters at the desired level and then use this mixture? its not gonna raise the alkalinity level only.

 

[BriDroid]

i have a question about that All For Reef stuff. for the all in one mixture. (that isn't as expensive as I was guessing it would be)

if that all in one mixture has all the elements combined..do you first need to get all your parameters at the desired level and then use this mixture? its not gonna raise the alkalinity level only.

If you’re using a decent salt mix, everything seems to fall in line. I use Tropic Marin Pro Reef and dose All For Reef. I use dKH as my guideline for dosing. When I do test calcium, it’s always in line with where it needs to be as well as magnesium. It seems to be a very good system.

 

[KStatefan]

i have a question about that All For Reef stuff. for the all in one mixture. (that isn't as expensive as I was guessing it would be)

if that all in one mixture has all the elements combined..do you first need to get all your parameters at the desired level and then use this mixture? its not gonna raise the alkalinity level only.

Correct

Adjust to the levels you want the dose All for Reef to maintain.

 

[reef tank 2.0]

got it, thank you

 

[Marbles]

pH raising us almost always a benefit, not a detriment.

There are many ways to supplement alkalinity, and I’d suggest at this stage that Tropic Marin AFR might be a good choice.

But sodium bicarbonate and carbonate are also good choices, as is sodium hydroxide if you want an even bigger pH boost.

pH raising us almost always a benefit, not a detriment.

There are many ways to supplement alkalinity, and I’d suggest at this stage that Tropic Marin AFR might be a good choice.

But sodium bicarbonate and carbonate are also good choices, as is sodium hydroxide if you want an even bigger pH boost.

I'm having trouble with low alk and ph consistently. Calcium is always high to. Not dosing anything at the moment. PH 7.5, Alk 5.3 and Calcium 555 all with Hanna Checkers. What would you recommend I try?