Is baking soda a buffer and pH adjuster?

[MDPinUSA]

Increasingly I have been asked by numerous marine hobbyists about the use of baking soda as a buffer or pH adjuster over the last few months.

There are many ways to set up and maintain a salt water aquarium. Some ways are infinitely easier and vastly more rewarding than others.

One developing trend is on-line DIY information that can bring more headaches than rewards to marine aquarium keeping.

It would appear that some on-line aqua gurus are touting the use of baking soda as a cure-all for alkalinity and pH problems.

With a little surfing, it is evidenced that proponents of baking soda are: a) Testifying this is a cheap alternative to the proper item(s). b) Indicating this is a inexpensive remedy to correct poorly make marine salts. c) Attempting to exhibit some level of quasi scientific qualifications they do not possess. d) Simply arm chair chemists and low end marine aquarium keepers striving to gain superficial recognition as on-line aqua gurus.

This thread is offered in three sections.

Section 1 provides some detailed information regarding baking soda.

Section 2 offers information for the average marine aquarist.

Section 3 cuts to the case about baking soda.

SECTION 1

Baking soda in its pure form is sodium bicarbonate (Na HCO3) without any additives. It is sold in small packages to consumers for a variety of applications. When sold as baking soda, there is usually an additive that allows for the material to be free flowing.

The anti caking or free flowing agent of choice is usually aluminum silicate. Al Si, or other forms of silicates used as free flowing additives or found as impurities in low grade marine salts and ill formulated supplements will most likely produce unwanted algae. Some food grade common salts contain an anti caking or free flowing agent that is not listed on the consumer package. (not necessarily Al Si)

Na HCO3 is produced by more than one manufacturer in more than one grade. High purity Na HCO3 is produced without any additives. Some salts without additives can cake and resemble blocks of concrete. Hence. the addition of a free flowing or anti caking agent is employed with most brands of baking soda that are offered in consumer packages.

We receive 40,000+ pounds of high purity sodium bicarbonate without additives on a regular basis. Caked material is pulverized utilizing high grade stainless steel equipment in an environmentally controlled temperature and humidity enclosure. This technique allows this and other high purity salts (without additives) to be employed as a uniform particle powder for compounding into various scientific and marine aquarium related formulations.

SECTION 2

A 10% solution of sodium bicarbonate has a pH of about 8.05. The pH of marine aquarium salt water solution with continual or large additions of sodium bicarbonate tops out at pH 8.2.

Unremitting or massive amounts of baking soda cannot bring the pH of natural sea water up to or stabilize at the natural pH equilibrium of 8.35-8.5. Likewise additions of baking soda with marine salts (SG 1.024-1.026) used as a sea water substitute for keeping delicate, exotic and costly marine organisms will not reach a pH value over 8.2.

If baking soda is continually added in an attempt to control alkalinity and pH (vs. a true BUFFER), the result will be dramatically increased alkalinity. However the pH will be prevented from reaching the optimal level of 8.4. The ultimate result is unbalanced water parameters and the development of unwanted algae.

Some other carbonates that will increase alkalinity in salt water aquariums are: Mg CO3, Ca CO3, K CO3, Na CO3, Sr CO3, etc. however these and some other carbonates are insoluble and/or will drive pH levels beyond 10.

The use of a scientifically researched, developed, tested and manufactured TRUE BUFFER with KH Generator that utilizes the preferred grades of ingredients, in the proper proportions is simply the smart, best and proper choice.

SECTION 3

If baking soda is expected to adjust alkalinity and pH to approximate NSW or to the parameters found in a suitable marine salt, we are in for a rude awakening. Baking soda (like some other carbonates) will increase alkalinity, but cannot yield the proper pH.

Limitless additions of baking soda will create an unbalanced solution that will be most difficult to adjust to acceptable parameters of: alkalinity and pH.

As undesirable algae is cultivated, ultimately a deprivation of essential dissolved oxygen can be observed. Controlling, reducing or eradicating the unwanted algae resulting is impossible if baking soda is still added.

High alkalinity (dKH or KH) can harm some delicate corals. The alkalinity of NSW is 6-7, depending on which test kit you are using. A KH of 10.5+ has demonstrated to harm some SPS corals.

NSW has a pH of 8.3-8.5. A pH of 8.2 with high alkalinity is not only unnatural, it creates a slew of internet threads ad posts from confused marine aquarium keepers asking: what is wrong, how to change this situation, etc.

In some applications the use of a costly and sometimes difficult manage external support equipment can reduce unwanted algae. However during the time of adjusting such equipment their can be dramatic shifts in pH.

Hobbyists who attempt to save a few pennies on an elaborate system may never see their systems operate at the true potential .... if they use inappropriate DIY nonsense, additives, supplements, marine salts, foods support equipment, as this approach generates more problems than pleasure from our hobby investment.

[Thomas]

So what are you trying to say? When the box of baking soda in my fridge is worn out I should not use it in my reef tank?

[Gecko]

Hmmmmmmm Baking soda from fridge into tank equals proper PH & alkalinity. This is a great idea. Why didnt I think of that?

[MDPinUSA]

People are actually using baking soda usually used in the fridge in their reef aquariums. This is starting to become wide spread.

From what I gather, it is all about saving a little money and not buying a suitable buffer made for marine aquarium use.

It is used by folks that understand they must first fix a defecient marine salt product prior to use.

[cUddlefish]

Some time ago MDP told me that baking soda was not a good idea because of the anti caking agents in it. I am one of those people who will test the things I hear to make sure it is true (or else I am like the mom and dad in the movie "Time Bandits"). I promptly read the ingrdients on a box of Arm and Hammer Baking Soda. It listed Sodium BiCarbonate only. So I added it into my 20 gallon quarantine tank with a power head and a couple of pieces of base rock. The "Q" tank has been in operation for about a year and gets no light and regular changes of NSW. The ph rose slightly (the buffering capacity of the water was low since it was NSW) but the kicker was this: Within a week, the outbreak of cyanobacteria was jaw dropping. In 20 years of maintaining reef tanks, I had never experienced cyano. I had never used baking soda either. It appears that the FDA does not require Aluminum Silicate to be listed as an anti caking ingredient either because it is not considered an ingredient in food or it is chemically inert or not reactive. After doing a large water change with NSW, the pH went back to normal and the cyano went away. I have not seen it since. I realize this is anecdotal but it is also demonstrative.

I still use Baking Soda extensively though......as a nasty tasting antacid.

[ChuckG]

Interesting.

This brings up another question though. How about the grocery store pickling lime that a lot of folks are using as kalkwasser?

[Thomas]

Here's another one. Grocery store borax as a pH verification. Does it really work?

[MDPinUSA]

Verification? Please define.

Borax is commercial grade sodium borate. These are the bead shaped particles found in at least one well known "buffer" marketed and sold to marine aquarium keepers.

Borate "B" is a very small part of the buffering system or buffering platform in some brands of marine salts.

We have formulated marine salts without the addition of B. These formulations were all bio assay successful (ability to allow natural cell division in sea urchin and various larva rearing projects).

Larva from amphiprion ocellarus was raised to adulthood. These adults reproduced and ultimately F3 Amp. ocellarus were raised to adulthood in solutions without the addition of borate in the marne salt formulation.

At the same time, synthetic sea water formulations were compounded that included B at NSW concentrations. There appeard to be no difference in larva numbers or survival between systems were B was present vs. B found as an impurity.

Mahi Mahi was raised in captivity through several generations at the California Academy of Science in the mid 1980's with marine salts we provided where B was not added to the formulation.

This strongly suggests B (like a few other elements) has no life giving properties when used in synthetic sea water.

Sodium borate is available in several purities. If hobbyists use borate for their individual aquarium use, I would hope that it is higher purity than (borax) hand cleaner.

Borate is not easily tested with accuracy by the home marine hobbyists. Borate is found at 4.6 ppm. in NSW at 35 ppt. (page 7, Artificial Seawaters Formulas and Metholds. Bidwell & Spotte).

Without proper testing and monitoring of additions (of any supplement), it is highly possible to overdose with the ramdom addition of any ion. The results can be catistrophic.

Most hobbyits continually fiddle and fool with their marine aquariums. This is part of the enjoyment of salt water aquarium keeping.

However, an alarming number of hobbyists are simply diven by the insatable desire to use lower and lower cost items. Sooner than later, something(s) will be introduced into the closed system that will cause more unexpected problems than hobby enjoyment.

[Thomas]

There are several articles that can be found on the web by typing in pH verification using grocery store borax. I believe this is for making a cheep solution to check pH meters. Chemistry and the Aquarium - 58k
reefkeeping.com/issues/2004-09/rhf/index.php - 59k

[MDPinUSA]

This thread is going from baking soda to a variety of DIY additions that are stupefying at best.

I would like to make shorter posts... but......

Thomas: Interesting link. A lot of reading that offers basic info. in a complex way.

Most of what is offered describes the negatives associated with various DIY or home brew approaches to marine aquarium water parameter adjusting.

Unfortunately there are many readers of this information that will interpret this as a guide to a DIY approach to aquarium keeping. -- I see it as more of a cautionary guide to the negatives of employing many of the approaches listed.

I stand by my previous statements. ".... higher purity than borax hand cleaner...." And... ".... sooner than later.... "

Chuck: Pickling lime or kalkwasser is simply calcium hydroxide.

Here are three (of many) factors to consider prior to the use of calcium hydroxide.

1) Checking a chemical reference hand book will provide enough cautions for the educated aquarist to realize and understand calcium hydroxide is a caustic salt.

It should be handled with great care. This includes: eye protection, respirator and IMO gloves.

2) The more calcium hydroxide that is added to the system, the faster alkalinity will drop and pH can sky rocket.

3) Continual additions of calcium will yield a solution that will soon be out of balance as no consideration is given to Mg, K, So4, etc.

Adjusting the major ions in a sea water medium should be approached with understanding and responsibility. It is always best to make a water change with a balanced marine salt vs. depending on continual additions of one or more major elements. Then having to introduce minor components (buffers, pH adjusters, etc.) to compensate for the improper prior water chemistry modifications.

Like most DIY additives or supplements, there can be a fine balance between achieving the desired results vs. creating unexpected problems.

The root cause of what is confusing, conflicting and many times misinformation that results in less than an optimal approach to aquarium keeping is...... -- The promotion of many supplements (IMO, marginal, questionable or useless) in flashy packages with associated advertising by less than qualified kitchen kemists™ and garage fabricators.

A few on-line aqua gurus™ understood the simplicity of purchasing a 50 pound package of commerical grade calcium chloride, calcium hydroxide, etc. then posting on-line what the fancy packages actually contained vs. bulk buying.

This gave rise to additional kitchen kemists™ and garage fabricators introducing a slew of new brands, with the same low tech, commercial grade salts, in yet fancier packages. For the most part this is an under financed group of unsophisticated opportunists that can only afford to promote on the internet.

IMO the aqua gurus™ that posted this information did so to bolster their status with home aquarium keepers. -- In some circles, they are worshipped as divine financial saviors. As they gain status within the cost oriented group.

The next step in the progression of much internet DIY is under financed hobbyists wanting to believe, then posting on-line that borax hand cleaner, commercial grade baking soda and at the shallow end of the gene pool, the use of ice melting salts as a calcium addition.

The latest trend is for commercial grade chemicals being sold in bulk sizes in unmarked Ziplock® or Food Saver® bags. In some cases these low grade chemicals are marked with a gummed label.

None of these items are sold in reputable aquarium or pet shops. They found only on the internet.

IMO, this is key. From what I have witnessed, very little if any attention has been given to consequences of adding low purity (introduction of unwanted impurities) chemicals into the closed aquarium system. A plethora of additional DIY remedies abounds to compensate for the first round of improper chemical additions.

However, baking soda, hand cleaner, pickling lime, ice melting salt and peanuts are cheap.