Raising your Aquarium's pH Level
© Albert J. Thiel - April 1998 - Update 5
Introduction
More Information on the Dropping pH Syndrome
How can we influence the pH?
Adding buffers
A further look at the problem
Adding Kalkwasser - KW- (Limewater)
A First Step in solving this
A Second Step - Water Changes
The Goals of water changes
Additonal Steps that may be necessary
-Introduction
Not so infrequently, hobbyists struggle with a pH falling "syndrome" that can occur at any period in the lifecycle of the aquarium. Sometimes it happens when the tank is fairly "new" and sometimes it will happen to aquariums that are years old. In fact, it is not uncommon to see it happen more often in older tanks. The reasons will become clearer as you read on. It has to do with the build-up of acids of various kinds in the water.
Their pH may be too low to begin with, when they just start their aquarium, and/or it may become too low after the cycle is just completed. As the tank ages, the pH may suddenly start to take a drop and sort of go on a lower and lower sliding scale. More often than not the hobbyist is at a loss to understand why this is happening and how to deal with it.
The falling pH syndrome can "really" occur at any time in the life cycle of the aquarium. The fact is that it does happen and that many hobbyists are at a loss understanding how to counteract this chemical tendency. There is nothing unusual and nothing dangerous about this as long as you catch it soon enough and take measures to bring the pH back up. This document and others in the NetClub Library explain how to do so.
We all know that water quality varies. It varies a great deal in fact. Even water quality readings taken in the morning will not match up with readings on the water chemistry taken at night on that same tank. This is a normal occurance and results from all the chemical and biochemical processes going on in the aquarium. Note also that we do not have any control over most of these reactions.
Note also that the water quality of your raw water will vary as well depending on time of the year and your geographical location. This is not the topic of this article though. This one deals with the changes that happen to and with aquarium water. Why are there changes?
They can be attributed to various causes, many of which are not always that obvious to the hobbyist:
-You are using R.O. (reverse osmosis) water that even after the salt is added has a pH that is too low.
-You are using a D.I. (deionizer) which produces the same as above.
-You are using a combination of the above two filtration methods and end up with the same results.
-The salt you use is low in alkalinity (dKH) to begin with. It may not have enough carbonate and borate content.
-You have a high biological load. This produces lots of acidity of various kinds which lowers the buffer (dKH) and ultimately the pH.
-You overfeed the animals in your tank creating a high amount of organic waste that decomposes and results in a drop in the dKH and then the pH (as a result of acids that are produced in mineralization)
-You use chemical filtration that depletes your buffer.
-The live rock and substrate (if any), or the coral rubble and so on, in the tank do not buffer your water sufficiently and thus reduce your pH because the buffer remains too low. The buffering layer underneath the live sand is no longer buffering (this tends to happen to aquariums that have been set up for some time)
-The buffer is skewed towards the bicarbonates. This leads to a high dKH and a low pH level. Bicarbonate has a pH that is lower than what you want in your tank (e.g. baking soda typically has a pH of only 7.7-7.8)
-Your buffer may be lacking borates
-Your buffer may be lacking carbonates
-Your buffer may have too many bicarbonates.
-A combination of all of the above 3 buffer problems.
These represent quite a number of reasons why the pH may be low. The list is not exhaustive though.
Some rock or other material in the tank may be leaching bicarbonates into the water. Bicarbonates tend to pull the pH down. For example, the natural pH of sodium bicarbonate (baking soda) is 7.7-7.8 only as I indicated. If your buffer is skewed towards bicarbonates your pH will be low even though you main register a high alkalinity
-More Information on the Dropping pH Syndrom
The pH of an aquarium is an expression of the relative presence of acids and bases in ionic form. What happens is that when the amount of acidic ions (to phrase it simply) outnumbers the caustic ones, the pH of the water will be low.
The opposite is, of course also true: when their are more alkaline ions in the water than acidic ones the pH will, naturally, be higher.
Depending on which ions are more prevalent, your pH will tend to be either lower or higher.
Since it is known what affects the pH, it is possible for you to intervene and add certain compounds to the water to make the pH rise. These compounds are those portions of the buffer that have a tendency to push the pH upwards.
Carbonates and Borates will make the pH rise. Bicarbonates have a tendency to make the pH fall.
The mixture or the proportion of these compounds in relationship to the total buffering compounds (the % of each) tends to influence where the pH will stabilize itself at.
If your aquarium has lots of bicarbonates in the buffer, yet few carbonates and borates, the pH will be more influenced by the bicarbonates. As we have seen this will lead to a low pH level.
It should be obvious by now that having the correct proportions of these buffering compounds in dissolved in your water is important and is what ultimately ensures that your pH will not demonstrate a falling tendency.
Our task, therefore, as hobbyists, is to adjust the buffer in such a manner that the buffer contains all necessary compounds and that these compounds are, and remain, present in such quantities that the pH does not drop to levels lower than we wish it to be.
-Influencing the pH Level
-Adding Buffers
As the explanations above made rather clear in my opinion, a distortion in the make-up of the buffer can, and will more than likely, result in a drop of the pH level. When this is just a simple distortion, rebuffering the water with a complete buffer (one that contains all 3 compounds mentioned earlier) will re-establish your pH. Your "only" task is to add enough buffer, slowly, yes slowly and over time, until the desired pH is reached again.
You then observe the pH for a few days by testing it, and add more buffer, if necessary, until you are satisfied that the pH has stabilized itself and no longer fluctuates downwards.
Theoretically the pH should be at its lowest in the morning and should slowly rise as the day goes by, and photosynthesis takes place. Since this removes carbon dioxide from the water, the pH will have a natural tendency to rise. Towards the end of the day the pH should be higher than it was in the morning.
A further look at the problem
What was just described is the simplest of all the possible scenarios. Unfortunately, it is the one least likely to occur. More often than not, the problem is deeper rooted, and a far greater intervention on the hobbyist's part is necessary.
The low pH problem and the process associated with resolving it, is more complicated and will certainly take a longer time to solve than the one just described where only buffers are added to solve the problem.
When the pH is out of balance for several reasons, the solution is obviously much more complicated, as we shall see later in this article. Complicated is maybe not the correct word, complex is better.
When the pH is low, and is low on a continuous basis, your problem is of a totally different nature. In fact it is, more than likely, due to a combination of circumstances, each of which may require a totally different approach, or it may take a combination of methods to really solve your problem.
(CONT)
© Albert J. Thiel - April 1998 - Update 5
Introduction
More Information on the Dropping pH Syndrome
How can we influence the pH?
Adding buffers
A further look at the problem
Adding Kalkwasser - KW- (Limewater)
A First Step in solving this
A Second Step - Water Changes
The Goals of water changes
Additonal Steps that may be necessary
-Introduction
Not so infrequently, hobbyists struggle with a pH falling "syndrome" that can occur at any period in the lifecycle of the aquarium. Sometimes it happens when the tank is fairly "new" and sometimes it will happen to aquariums that are years old. In fact, it is not uncommon to see it happen more often in older tanks. The reasons will become clearer as you read on. It has to do with the build-up of acids of various kinds in the water.
Their pH may be too low to begin with, when they just start their aquarium, and/or it may become too low after the cycle is just completed. As the tank ages, the pH may suddenly start to take a drop and sort of go on a lower and lower sliding scale. More often than not the hobbyist is at a loss to understand why this is happening and how to deal with it.
The falling pH syndrome can "really" occur at any time in the life cycle of the aquarium. The fact is that it does happen and that many hobbyists are at a loss understanding how to counteract this chemical tendency. There is nothing unusual and nothing dangerous about this as long as you catch it soon enough and take measures to bring the pH back up. This document and others in the NetClub Library explain how to do so.
We all know that water quality varies. It varies a great deal in fact. Even water quality readings taken in the morning will not match up with readings on the water chemistry taken at night on that same tank. This is a normal occurance and results from all the chemical and biochemical processes going on in the aquarium. Note also that we do not have any control over most of these reactions.
Note also that the water quality of your raw water will vary as well depending on time of the year and your geographical location. This is not the topic of this article though. This one deals with the changes that happen to and with aquarium water. Why are there changes?
They can be attributed to various causes, many of which are not always that obvious to the hobbyist:
-You are using R.O. (reverse osmosis) water that even after the salt is added has a pH that is too low.
-You are using a D.I. (deionizer) which produces the same as above.
-You are using a combination of the above two filtration methods and end up with the same results.
-The salt you use is low in alkalinity (dKH) to begin with. It may not have enough carbonate and borate content.
-You have a high biological load. This produces lots of acidity of various kinds which lowers the buffer (dKH) and ultimately the pH.
-You overfeed the animals in your tank creating a high amount of organic waste that decomposes and results in a drop in the dKH and then the pH (as a result of acids that are produced in mineralization)
-You use chemical filtration that depletes your buffer.
-The live rock and substrate (if any), or the coral rubble and so on, in the tank do not buffer your water sufficiently and thus reduce your pH because the buffer remains too low. The buffering layer underneath the live sand is no longer buffering (this tends to happen to aquariums that have been set up for some time)
-The buffer is skewed towards the bicarbonates. This leads to a high dKH and a low pH level. Bicarbonate has a pH that is lower than what you want in your tank (e.g. baking soda typically has a pH of only 7.7-7.8)
-Your buffer may be lacking borates
-Your buffer may be lacking carbonates
-Your buffer may have too many bicarbonates.
-A combination of all of the above 3 buffer problems.
These represent quite a number of reasons why the pH may be low. The list is not exhaustive though.
Some rock or other material in the tank may be leaching bicarbonates into the water. Bicarbonates tend to pull the pH down. For example, the natural pH of sodium bicarbonate (baking soda) is 7.7-7.8 only as I indicated. If your buffer is skewed towards bicarbonates your pH will be low even though you main register a high alkalinity
-More Information on the Dropping pH Syndrom
The pH of an aquarium is an expression of the relative presence of acids and bases in ionic form. What happens is that when the amount of acidic ions (to phrase it simply) outnumbers the caustic ones, the pH of the water will be low.
The opposite is, of course also true: when their are more alkaline ions in the water than acidic ones the pH will, naturally, be higher.
Depending on which ions are more prevalent, your pH will tend to be either lower or higher.
Since it is known what affects the pH, it is possible for you to intervene and add certain compounds to the water to make the pH rise. These compounds are those portions of the buffer that have a tendency to push the pH upwards.
Carbonates and Borates will make the pH rise. Bicarbonates have a tendency to make the pH fall.
The mixture or the proportion of these compounds in relationship to the total buffering compounds (the % of each) tends to influence where the pH will stabilize itself at.
If your aquarium has lots of bicarbonates in the buffer, yet few carbonates and borates, the pH will be more influenced by the bicarbonates. As we have seen this will lead to a low pH level.
It should be obvious by now that having the correct proportions of these buffering compounds in dissolved in your water is important and is what ultimately ensures that your pH will not demonstrate a falling tendency.
Our task, therefore, as hobbyists, is to adjust the buffer in such a manner that the buffer contains all necessary compounds and that these compounds are, and remain, present in such quantities that the pH does not drop to levels lower than we wish it to be.
-Influencing the pH Level
-Adding Buffers
As the explanations above made rather clear in my opinion, a distortion in the make-up of the buffer can, and will more than likely, result in a drop of the pH level. When this is just a simple distortion, rebuffering the water with a complete buffer (one that contains all 3 compounds mentioned earlier) will re-establish your pH. Your "only" task is to add enough buffer, slowly, yes slowly and over time, until the desired pH is reached again.
You then observe the pH for a few days by testing it, and add more buffer, if necessary, until you are satisfied that the pH has stabilized itself and no longer fluctuates downwards.
Theoretically the pH should be at its lowest in the morning and should slowly rise as the day goes by, and photosynthesis takes place. Since this removes carbon dioxide from the water, the pH will have a natural tendency to rise. Towards the end of the day the pH should be higher than it was in the morning.
A further look at the problem
What was just described is the simplest of all the possible scenarios. Unfortunately, it is the one least likely to occur. More often than not, the problem is deeper rooted, and a far greater intervention on the hobbyist's part is necessary.
The low pH problem and the process associated with resolving it, is more complicated and will certainly take a longer time to solve than the one just described where only buffers are added to solve the problem.
When the pH is out of balance for several reasons, the solution is obviously much more complicated, as we shall see later in this article. Complicated is maybe not the correct word, complex is better.
When the pH is low, and is low on a continuous basis, your problem is of a totally different nature. In fact it is, more than likely, due to a combination of circumstances, each of which may require a totally different approach, or it may take a combination of methods to really solve your problem.
(CONT)