Sodium hydroxide

[Bakki]

Hi,

I was wondering why sodium hydroxide is not a more popular basis for 2 part solutions. The ones I see are based on carbonate/bicarbonate. curious to hear peoples thoughts.

 

[WhatCouldGoWrong71]

Hi,

I was wondering why sodium hydroxide is not a more popular basis for 2 part solutions. The ones I see are based on carbonate/bicarbonate. curious to hear peoples thoughts.

I've been using it for about 9 months now. I can't use it exclusively though, or better said - I don't want my PH > 8.50. I have Sodium Hydroxide on one DOS head and Sodium BiCarb on the other. I have rules written that Hydroxide >8.50 that head is off and the BiCarb head <8.51 and it is off. You cannot write it with an on statement (or I won't) but this keeps me pegged at 8.50ish. I have two tanks, I use this method on my mixed currently. I have Soda Ash on my other tank (SPS). The only negative thing I have to say is don't wear shorts and flip flops when mixing this stuff

 

[elysics]

Hi,

I was wondering why sodium hydroxide is not a more popular basis for 2 part solutions. The ones I see are based on carbonate/bicarbonate. curious to hear peoples thoughts.

Because it's dangerous. Carbonate is already not so great to get on skin or possibly eyes compared to bicarbonate, hydroxide will do proper damage.

No problem if you treat it with respect but one little flick of a droplet, or not washing your hands entirely/grabbing something that still has a crystal on it and rubbing your eyes after and you might be blind.

And not necessarily all containers and tubing will be resistant to it

 

[WhatCouldGoWrong71]

Because it's dangerous. Carbonate is already not so great to get on skin or possibly eyes compared to bicarbonate, hydroxide will do proper damage.

No problem if you treat it with respect but one little flick of a droplet, or not washing your hands entirely/grabbing something that still has a crystal on it and rubbing your eyes after and you might be blind.

Yeah, I wear full face mask plus breathing filters. I learned the hard way, just one little crystal will pucker your bunghole right up...

 

[Randy Holmes-Farley Verified Community Expert]

Hi,

I was wondering why sodium hydroxide is not a more popular basis for 2 part solutions. The ones I see are based on carbonate/bicarbonate. curious to hear peoples thoughts.

I have several diy recipes in various threads and you can see folks are using them:

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

 

[Miami Reef]

Hi,

I was wondering why sodium hydroxide is not a more popular basis for 2 part solutions. The ones I see are based on carbonate/bicarbonate. curious to hear peoples thoughts.

It’s relatively new, it’s caustic, reef stores (like BRS) don’t sell/promote it for safety reasons.

People use sodium hydroxide to make DIY soap. It’s only dangerous if you handle it incorrectly.

 

[Gtinnel]

I've been using it for about 9 months now. I can't use it exclusively though, or better said - I don't want my PH > 8.50. I have Sodium Hydroxide on one DOS head and Sodium BiCarb on the other. I have rules written that Hydroxide >8.50 that head is off and the BiCarb head <8.51 and it is off. You cannot write it with an on statement (or I won't) but this keeps me pegged at 8.50ish. I have two tanks, I use this method on my mixed currently. I have Soda Ash on my other tank (SPS). The only negative thing I have to say is don't wear shorts and flip flops when mixing this stuff

I’ve been mixing my solutions of sodium carbonate and sodium hydroxide to keep my ph about where I want it. I’m not sure why but I never even considered keeping them separate and having my doser select which one to use based off of pH readings.

As for the original question I agree it’s likely not commonly used because the risks of using it means that the major companies don’t sell it for aquarium use because of liability concerns. I’ve been using it for a while and I am cautious not to get it on me, but I don’t do or wear anything special when working with it.

 

[KStatefan]

It’s relatively new, it’s caustic, reef stores (like BRS) don’t sell/promote it for safety reasons.

People use sodium hydroxide to make DIY soap. It’s only dangerous if you handle it incorrectly.

I seems like there are a lot of people that do not take the safety precautions that they should.

I saw a reef video a few days ago where he suck started a siphon to drain his kalk reactor.

 

[Miami Reef]

I seems like there are a lot of people that do not take the safety precautions that they should.

I saw a reef video a few days ago where he suck started a siphon to drain his kalk reactor.

I’ve been wanting to make a how-to guide on properly mixing sodium hydroxide in a 1 gallon container.

About the siphon to drain the kalk…yikes.

 

[Jposch]

TLDR= wouldn't recommend using it solely unless tank is 1dkh/day or less.
Lye can be used quite effectively, but if alk demand is high enough. You'll need to supplement with soda ash. I mix the the 2. About 6 parts lye to 1 part soda ash.
One reason it's less popular is that it is hazardous. You must wear safety glasses at a minimum. Gloves and an apron strongly recommended. Also, when dissolving, it is HIGHLY exothermic, and can melt right through a plastic (HDPE) container. when adding to water, it can clump together, creating a "hot spot" making it even more concerning. I fill my wash tub with ice water and then fill jug with rodi, and slowly add the lye.
Strong lye solutions degrade silicone dosing lines fairly quickly as well.

You also need to add the lye into a real high flow area of the sump to avoid abiotic precipitation.
I'm switching to only soda ash for my main system soon. I cannot maintain over 8dkh without pH going to 9pH. There is zero benefit to exceeding 8.6pH at peak. Above that, and it'll be a long, losing battle with abiotic precipitation.

 

[Miami Reef]

I dissolve hydroxide in glass borosilicate beakers with a magnetic stirrer and use HDPE and LDPE containers and dosing lines.

 

[Dan_P]

I seems like there are a lot of people that do not take the safety precautions that they should.

I saw a reef video a few days ago where he suck started a siphon to drain his kalk reactor.

Generally, our imaginations are limited and not trained to evaluate risk. The ideal process control for the reef aquarium is fail-safe or intrinsically safe. This means there are no or very unlikely situations where hydroxide can possibly raise the pH to a dangerous or lethal level. By their very nature of active control, dosing pumps are not intrinsically safe. The siphon formation or valve stuck “on” make the use of sodium hydroxide unwise for the reef aquarium.

 

[Randy Holmes-Farley Verified Community Expert]

TLDR= wouldn't recommend using it solely unless tank is 1dkh/day or less.
Lye can be used quite effectively, but if alk demand is high enough. You'll need to supplement with soda ash.

The concern about the pH getting too high would be case by case, and IMO, that 1 dKH cutoff is too low.

Many people use hydroxide from kalkwasser for higher demand than 1 dKH. I did for 20 years.

 

[Randy Holmes-Farley Verified Community Expert]

The siphon formation or valve stuck “on” make the use of sodium hydroxide unwise for the reef aquarium.

Of course, it can be used in exactly the same ways that one uses and controls kalkwasser. Do you believe it is too risky?

 

[elysics]

Generally, our imaginations are limited and not trained to evaluate risk. The ideal process control for the reef aquarium is fail-safe or intrinsically safe. This means there are no or very unlikely situations where hydroxide can possibly raise the pH to a dangerous or lethal level. By their very nature of active control, dosing pumps are not intrinsically safe. The siphon formation or valve stuck “on” make the use of sodium hydroxide unwise for the reef aquarium.

You can prevent siphons with 100% certainty, just have the dosing containers lower than the end of the dosing line ( and the end of the dosing line in the air, not in water). At least the dangerous kind of siphon where too much is dosed.

Pumps being stuck on is a more tricky poblem, but that too can be mitigated with backup systems that disable the pumps when they are not supposed to run.

 

[Randy Holmes-Farley Verified Community Expert]

You can prevent siphons with 100% certainty, just have the dosing containers lower than the end of the dosing line ( and the end of the dosing line in the air, not in water). At least the dangerous kind of siphon where too much is dosed.

Pumps being stuck on is a more tricky poblem, but that too can be mitigated with backup systems that disable the pumps when they are not supposed to run.

Or a pump that is on most of The time, and if it gets stuck on, only adds a little more than usual.

I did that with kalk on a float switch.

 

[Jposch]

The concern about the pH getting too high would be case by case, and IMO, that 1 dKH cutoff is too low.

Many people use hydroxide from kalkwasser for higher demand than 1 dKH. I did for 20 years.

You are right. I forget that I also use kalkwasser. (16L/1,200L tank)
In another system that uses about half as much kalkwasser (top off to volume ratio) I was able to add a bit more lye. At 3dkh/day, I'm switching that system to a soda ash/lye mix as pH is getting on the high end, and I'm tired of acid soaking pumps and some end up with broken impeller shafts. With magnesium is 1350ppm+, and po4 at 0.1ppm, any other precipitation inhibition measures are likely to impact biological calcification.
As far as I can tell, higher alk and modest pH (11-12dkh, pH peaking 8.5) gives better growth than much higher pH and modest alk. (8dkh and pH peaking 8.7+) much less abiotic precipitation as well.

Or a pump that is on most of The time, and if it gets stuck on, only adds a little more than usual.

I did that with kalk on a float switch.

Agreed. I dose everything on continuous duty peristaltic pumps. I figure the risk of the doser deciding to change the rate for no reason is extremely minimal compared to a unit that doses in spurts several times a day.

 

[Christoph]

Hi everyone,

while NaOH has for sure advantages to use it as alkalinity supplement (binding of CO2, thus a strong impact on pH, high concentration possible) i do strongly advise against its use for the end customer.

NaOH is a very caustic substance (much worse so compared to many acids such as muriatic acid), and a drop of NaOH solution into the eye is likely to cause permanent and serious eye injury. When handling NaOH solutions of high concentration proper personal safety equipment is in order. Otherwise it is just an accident waiting to happen.

And this is from someone who is trained to work with real nasties such as organolithium compounds or highly radioactive substances, so i do not have any chemical-phobia in general ;-)

Best regards,
Christoph

 

[Dan_P]

Of course, it can be used in exactly the same ways that one uses and controls kalkwasser. Do you believe it is too risky?

Great question. I’ll bite.

I feel the answer should be “too risky” when the failure mode dumps the entire reservoir into the aquarium AND the pH becomes dangerous or lethal. The use of either chemical can be rendered “dosing safe” by reservoir size, though I can see that such a solution could become tedious with the need for more frequent reservoir refills. Now let’s get into the area of acceptable risk.

I would really, really hate to harm or kill my aquarium charges, and therefore, the risk-benefit ratio is too high to use such a pH/alkalinity control method. Now suppose killing my aquarium charges is just an inconvenience. Then I would be more likely to use the dosing method.

 

[Randy Holmes-Farley Verified Community Expert]

Hi everyone,

while NaOH has for sure advantages to use it as alkalinity supplement (binding of CO2, thus a strong impact on pH, high concentration possible) i do strongly advise against its use for the end customer.

NaOH is a very caustic substance (much worse so compared to many acids such as muriatic acid), and a drop of NaOH solution into the eye is likely to cause permanent and serious eye injury. When handling NaOH solutions of high concentration proper personal safety equipment is in order. Otherwise it is just an accident waiting to happen.

And this is from someone who is trained to work with real nasties such as organolithium compounds or highly radioactive substances, so i do not have any chemical-phobia in general ;-)

Best regards,
Christoph

While I understand the concerns about human safety, and certainly do not want to suggest that folks not be very careful, I'm surprised that so many folks view sodium hydroxide as a lot different than kalkwasser. If the reason to elect sodium hydroxide over calcium hydroxide is the evaporation limit, then one might make it only a little stronger than kalkwasser, and not nearly as strong as a variety of existing consumer products, such as clogged drain openers.