Some results from sodium hydroxide dosing

[blasterman]

I've been testing sodium hydroxide dosing for pH boosting the past few days and promised some comments. I wanted to wait a bit for longer results, but am pretty geeked so far at results. Also need Randy to help confirm my results are in the ball park from a math point of view.

1/8 teaspoon of dry sodium hydroxide boosts my 20l from 8.15 to around 8.5 pH. I'm using a Salifert kit which did match my last electronic meter before it died, but wet kits have their limits. I will get a Hannah if Randy confirms I'm not hallucinating.

From what I'm seeing in terms of immediate growth improvements and absurdly easy dosing, well, C02 scrubbers need to be tossed in the dumpster. An immediate 30% increase in alk consumption for starters. Waiting for Randy's input. I know he's talked about sodium hydroxide dosing before, we just haven't been listening.

 

[Righteous]

Sodium hydroxide is also going to raise your carbonate alkalinity. I also believe that once you have full gas exchange the pH is going to go back down.

So you’re not really accomplishing the same thing as a CO2 scrubber (or outside air intake and good gas exchange).

 

[blasterman]

Are you serious dude?

A C02 scrubber works by blowing air over sodium hydroxide pellets and reducing C02 by some trivia amount. Then injecting that into your tank and hoping it displaces more saturated CO2 levels. Ive lost count how many complaints about people getting barely any results and blowing through pounds of sodium hydroxide pellets in a few weeks. Or having to result to looping it through skimmers.

Basically a CO2 scrubber is like taping a motrin to your forehead to solve a headache. Sodium hydroxide dosing is swallowing it.

My windows *are* wide open. I live in a metro area and my pH never gets higher than 8.15.

The amount of alk increase dry sodium hydroxide produces is about the same as sodium bicarb. Took awhile of digging to find Randy's comments on this. Seems to be about right. My tank consumes a bit less than a full teaspoon of sodium bicarb per day. So, the quantum mechanics here is 1 teaspoon minus 1/8 teaspoon ...might have to call a 3rd grader in on that.

Sorry to be short, but I just raised my tank pH significtly with a penny's worth of sodium hydroxide and got a big jump in alk consumption in 48 hours. Why in the world would you want to keep using a scrubber when you can raise pH for a fraction the price under more control ?

 

[Righteous]

Okay “dude”

Just adding some facts for those reading the thread. You can definitely use sodium hydroxide to raise alkalinity and pH. It’s totally fine to do that. However dosing really needs to be based off of Alkalinity, not pH.

Other people are using other methods to maintain alkalinity for various reasons, and a CO2 scrubber or outside air exchange works great.

Ultimately, assuming alkalinity is normal, low pH is always caused by CO2 in the water. So while you can certainly get a pH boost by using sodium hydroxide as an alkalinity supplement, lowering CO2 still is valuable for many and has its place. If you have great aeration, very low CO2 air, Alkalinity at correct levels, then the only reason for excessive low pH is one of the above is not being done, or your pH reading is off.

Anyway, none of this is new information. For those that can’t or don’t wish to deal with better aeration, or reducing CO2.. or for those who want to push pH higher than adequate values to potentially accelerate growth, then sodium hydroxide is a fine solution to maintain alkalinity while boosting pH.

 

[Randy Holmes-Farley]

Hydroxide has the highest pH raising effect of any possible alkalinity additive. It is part of my DIY ultra high pH two part systems:

Second New DIY Two Part Recipe with Higher pH Boost

In a previous thread, I posted a true two part DIY recipe: https://www.reef2reef.com/threads/new-diy-two-part-recipes-with-higher-ph-boost.344500/ But some folks may want to just swap the new ingredient into my 2/3 part recipe (as used by BRS, for example). Here's the original recipe link...

www.reef2reef.com

New DIY Two Part Recipes with Higher pH Boost

Here's a first crack at what may end up being multiple possible recipes for a DIY two part that either has a higher pH or can be made more concentrated than traditional two part recipes. This one has about twice the pH raising effect compared to a carbonate based two part, per unit of...

www.reef2reef.com

When I tested hydroxide, adding 0.5 meq/l (1.4 dKH) of alk to raw instant ocean, it boosted pH instantly by 0.65 pH units. The rise is smaller when added slowly as CO2 is drawn in.

 

[taricha]

1/8 teaspoon of dry sodium hydroxide boosts my 20l from 8.15 to around 8.5 pH.

where in your 20L system are you adding an 1/8 tsp of solid NaOH? (not that I would)

 

[Nerdist Aquarist]

If I can also chime in on this, I've switched over to dosing sodium hydroxide instead of BRS soda ash. It's only been 3 days so far, but on average my pH has increased by 0.2 (keeping same alkalinity level of 9). My windows are usually closed because of the south Florida heat and my CO2 level is usually slightly elevated, about 1100 ppm on my meter.

 

[Randy Holmes-Farley]

If I can also chime in on this, I've switched over to dosing sodium hydroxide instead of BRS soda ash. It's only been 3 days so far, but on average my pH has increased by 0.2 (keeping same alkalinity level of 9). My windows are usually closed because of the south Florida heat and my CO2 level is usually slightly elevated, about 1100 ppm on my meter.

Thanks for the info!

 

[FisheRare]

Are you serious dude?

A C02 scrubber works by blowing air over sodium hydroxide pellets and reducing C02 by some trivia amount. Then injecting that into your tank and hoping it displaces more saturated CO2 levels. Ive lost count how many complaints about people getting barely any results and blowing through pounds of sodium hydroxide pellets in a few weeks. Or having to result to looping it through skimmers.

Basically a CO2 scrubber is like taping a motrin to your forehead to solve a headache. Sodium hydroxide dosing is swallowing it.

My windows *are* wide open. I live in a metro area and my pH never gets higher than 8.15.

The amount of alk increase dry sodium hydroxide produces is about the same as sodium bicarb. Took awhile of digging to find Randy's comments on this. Seems to be about right. My tank consumes a bit less than a full teaspoon of sodium bicarb per day. So, the quantum mechanics here is 1 teaspoon minus 1/8 teaspoon ...might have to call a 3rd grader in on that.

Sorry to be short, but I just raised my tank pH significtly with a penny's worth of sodium hydroxide and got a big jump in alk consumption in 48 hours. Why in the world would you want to keep using a scrubber when you can raise pH for a fraction the price under more control ?

Which brand of sodium hydroxide do you use ?

 

[Randy Holmes-Farley]

Which brand of sodium hydroxide do you use ?

He's not been on in more than a year.

Any brand of food grade sodium hydroxide should be suitable. There are several DIY two part recipe threads using sodium hydroxide.

 

[k2-]

Hey @Randy Holmes-Farley a quick question - I intend to use naoh purely for ph purposes along with calcium reactor for most of my ca and mg (obviously alk will supplement too). I got confused when I read somewhere about adding sodium sulfite into the mixture as well ? Does that still hold true or just naoh is good to go ?

 

[Randy Holmes-Farley]

Hey @Randy Holmes-Farley a quick question - I intend to use naoh purely for ph purposes along with calcium reactor for most of my ca and mg (obviously alk will supplement too). I got confused when I read somewhere about adding sodium sulfite into the mixture as well ? Does that still hold true or just naoh is good to go ?

NEVER use sodium sulfite for anything.

You probably read one of the DIY two part recipes that uses sodium sulfate. That's a more complicated DIY than the ones I recommend below.

Sodium hydroxide alone is like adding sodium carbonate alone: it boosts alk and pH, does not add a balanced amount of calcium, and slowly raises sodium.

A better plan than sodium hydroxide alone is a DIY two part using sodium hydroxide, calcium chloride and Balling Part C (or less desirable, my DIY third part).

Second New DIY Two Part Recipe with Higher pH Boost

In a previous thread, I posted a true two part DIY recipe: https://www.reef2reef.com/threads/new-diy-two-part-recipes-with-higher-ph-boost.344500/ But some folks may want to just swap the new ingredient into my 2/3 part recipe (as used by BRS, for example). Here's the original recipe link...

www.reef2reef.com

 

[k2-]

Thanks Randy. It seems my use case is very little alk requirement and alot of Ph (probably by .2) so will stick to pure Sodium hydroxide and water changes.

 

[Miami Reef]

NEVER use sodium sulfite for anything.

Just curious, what would happen if someone were to mistakenly use sodium sulfite instead of sulfate? What effects would take place?

 

[Randy Holmes-Farley]

Just curious, what would happen if someone were to mistakenly use sodium sulfite instead of sulfate? What effects would take place?

I don’t know exactly what will happen, but it is widely used to prevent bacterial growth in foods (such as wine) , and it is a strong reducing agent that can react with many other chemicals, including O2, which might get seriously reduced.

 

[Gigajoulz]

@Randy Holmes-Farley , can you help explain how adding Sodium Hydroxide adds alk? Its my understanding the Alk comes from the CO2 which is converted to a carbonate or bicarbonate by the OH-. How do you measure how much alk is added to the system based on Na+ alone?

My goal is to us sodium acetate or calcium acetate to maintain alk levels with the added pH boost, while getting that daily carbon dose (while not over dosing the carbon)... but is the CO2 from the air the source of alk? Once the CO2 is converted to a carb/bicarb, the OH gets used up, lowering pH, correct? NaOH only raises pH until absorbed by CO2 overtime?

I'm thinking I could dissolve NaOH into vinegar to avoid CO2 completely in that reaction (where as soda ash or baking soda would put off CO2, dissolving some into the 95% water since the acetic acid is neutralized), and then dose the CH3COONa for nutrient control...with the added bonus of a mild alk and pH boost... I only have a few frags right now in our new 125 Gal after we just moved, so the demand for alk is quite low. I'm hoping that CH3COONa from NaOH will give me acetate firstly, and a mild pH boost as the acetate is used up. This would also make handling the additive safer since its not an extremally alkaline NaOH solution.

I'm just lost on how Na adds alk to the tank, since I'm reading some things that show that adding sodium acetate raises alk once the acetate is used up...or am I confusing this with calcium acetate? I'm not sure what the excess Na+ is doing without the acetate ion.

I appreciate your advise and explanations!

 

[Randy Holmes-Farley]

@Randy Holmes-Farley , can you help explain how adding Sodium Hydroxide adds alk? Its my understanding the Alk comes from the CO2 which is converted to a carbonate or bicarbonate by the OH-. How do you measure how much alk is added to the system based on Na+ alone?

My goal is to us sodium acetate or calcium acetate to maintain alk levels with the added pH boost, while getting that daily carbon dose (while not over dosing the carbon)... but is the CO2 from the air the source of alk? Once the CO2 is converted to a carb/bicarb, the OH gets used up, lowering pH, correct? NaOH only raises pH until absorbed by CO2 overtime?

I'm thinking I could dissolve NaOH into vinegar to avoid CO2 completely in that reaction (where as soda ash or baking soda would put off CO2, dissolving some into the 95% water since the acetic acid is neutralized), and then dose the CH3COONa for nutrient control...with the added bonus of a mild alk and pH boost... I only have a few frags right now in our new 125 Gal after we just moved, so the demand for alk is quite low. I'm hoping that CH3COONa from NaOH will give me acetate firstly, and a mild pH boost as the acetate is used up. This would also make handling the additive safer since its not an extremally alkaline NaOH solution.

I'm just lost on how Na adds alk to the tank, since I'm reading some things that show that adding sodium acetate raises alk once the acetate is used up...or am I confusing this with calcium acetate? I'm not sure what the excess Na+ is doing without the acetate ion.

I appreciate your advise and explanations!

Adding sodium hydroxide adds hydroxide. Hydroxide is one of the contributors to total alkalinity so there is no issue about it showing as alk. The sodium does nothing at all but sit there as sodium.

That said, adding hydroxide will instantly convert some of the bicarbonate to carbonate, and some CO2 to bicarbonate.

The system pH rises, putting the water at a deficit for CO2, and more CO2 enters from the air.

The net effect is higher pH, more carbonate, and more bicarbonate.

 

[Randy Holmes-Farley]

using vinegar to neutralize the NaOH is a fine plan, but it will more than offset the pH rise so don’t expect a pH boost relative to no hydroxide and vinegar dosing.

 

[brooksdw]

I have been dosing sodium hydroxide along with calcium hydroxide and I am getting some kind of precipitation in my algae turf scrubber and and bio pellet reactor. its accumulating in the sponge. only started when using the sodium hydroxide. it like a fine brown sand but it plugs up everything.

 

[Randy Holmes-Farley]

I have been dosing sodium hydroxide along with calcium hydroxide and I am getting some kind of precipitation in my algae turf scrubber and and bio pellet reactor. its accumulating in the sponge. only started when using the sodium hydroxide. it like a fine brown sand but it plugs up everything.

May be calcium carbonate. As pH gets higher, the tendency to precipitate rises sharply.