The power of hydrogen (pH) is one of the most critical water parameters for shrimp keeping and breeding. The optimum pH range depends on the shrimp species in the tank. Once you get this number, it is essential to stabilize the pH within this range.
pH is the measure of hydrogen ion concentration. The pH value in shrimp tanks is normally lowest in the early morning and highest in the afternoon. For the best water quality, the maximum pH fluctuation should not exceed 0.5. It is important to maintain a stable pH at a safe range because it affects the metabolism and other physiological processes of the shrimp.
It is most important that you keep your pH consistent. Shrimp are very sensitive invertebrates. Therefore, they do not like the changes very much. Of course, some shrimp species can be very hardy (Cherry shrimp, Snowball shrimp, Amano shrimp, even Ghost shrimp etc.) but it does not mean that they like it.
So, if you want to understand pH at a slightly deeper level, I will try to give you more of a background as to:
- What pH is.
- Why pH is important.
- How it affects our shrimp.
- Correlation between pH and kH.
- How to lower pH in a shrimp tank.
- How to increase pH in a shrimp tank.
What is pH
pH “potentia hydrogeni” or “pondus hydrogeni” is the logarithm of the hydrogen ion concentration in a solution, with the sign changed from positive to negative.
Did you understand it? What does it mean … in English?
In order to understand the principle, we have to start by talking about the water molecule first. Do not worry, I will try to keep it very short, simple and with pictures.
- 2 Hydrogen atoms (have a positive charge (H+)).
- 1 Oxygen atom (partial negative charge on another side of the oxygen (O).
Oxygen is very greedy when it comes to electrons. It can pull the electrons towards the side with a negative charge. If we add another molecule of water, sometimes that attraction is so great that this hydrogen atom will actually become detached from the water molecule and it will become attached to another water molecule.
- Hydronium (H3O+). It is going to have a positive charge.
- Hydroxide ion (OH-). It is going to have a negative charge.
Therefore, the pH stands for the power of Hydrogen. In other words, pH is the amount of Hydrogen (H+) but it could also be the amount of Hydronium (H3O+) or the amount of just free Hydrogen ion (OH-) inside the water. Actually, it really does not matter much because the result is the same.
How do we get 7 (neutral) pH
In regular distilled water, the chance of Hydronium (H3O+) or Hydrogen (H+) occurring is extremely rare. Basically, it is a 1 in 10,000,000 chance that we are going to have Hydronium (H3O+).
Now, let’s put this all in the equation of pH. Do not worry, we are almost done with science.
pH = −log10 [H+] or pH = −log10 [H3O+]
Note: remember, for our calculations, H+ is also the same as the Hydronium (H3O+). Those are essentially the same thing. I will continue to describe it that way [H+] since the majority of people have been taught it that way.
Let’s replace H+ with 1 in 10,000,000 chance of getting it.
pH = −log10 [1 in 10,000,000]
We take the negative log and write 1 in 10 million in scientific notation.
pH = −log10 [1 in 10-⁷]
If you put these numbers in your calculator and if we take the negative log of 1 times 10 to the negative seventh, we get 7.
pH = 7 (neutral)
It means that the concentration of Hydrogen (H+) is going to be relatively small. Consider it as a balance. That is why we call it neutral. However, if we ever have a value greater than 7 it is going to be a Base (Alkaline) and if it is ever lower than that then it is going to be an Acid (Acidic).
pH Fluctuations in Shrimp Tanks
The pH values are represented on a logarithmic scale ranging from 0 to 14. The lower we go on the scale the more Hydrogen ions will have in solution and vice versa.
Important: Logarithmic means that, each pH value is 10 times more acidic than the next value. For example, pH 7 is 10 times more alkaline than pH 6 and 100 times (10 times 10) more alkaline than pH 5! Just think about it. That as a lot of change. That is what stresses out our shrimp.
There are several biological processes, which are responsible for reducing or increasing the pH in our shrimp tanks all the time. For example:
It is a vital biochemical process, which is responsible for the oxidation and detoxification of ammonia to nitrite and nitrite to nitrate. This process generates the release of 2 free protons and because it is happening 24/7 in high amounts it is responsible for lowering the pH.
It takes place during the day when CO2 is removed (by plants) from the water column thus resulting in the consumption of Hydrogen ions (OH-). This is why the pH of a planted aquarium will gently increase throughout the day. In the nighttime, we have more CO2 present in the water. As a result, the lower your pH will become.
- Active Substrate
Active (buffered) substrate in the shrimp tank will also change the pH level by leaching the acidity.
It is important to understand that in our shrimp tanks the pH is always changing. Some shrimp species are extremely sensitive to pH and may require a narrower pH range to remain healthy. Our primal task is to keep it stable within a certain range.
Examples of pH and Types of Shrimp
|Bamboo shrimp||6.5 – 7.5||6.0 – 8.0|
|Caridina cf. babaulti||6.5 – 7.5||6.2 – 8.0|
|Snowball shrimp||7.0 – 7.5||6.0 – 8.0|
|Crystal red shrimp||6.6 – 6.9||6.2 – 7.2|
|Ghost shrimp||7.0 – 7.4||6.5 – 8.0|
|Amano shrimp||7.0 – 7.4||6.5 – 8.0|
|Cherry shrimp||7.0 – 7.5||6.0 – 8.0|
||7.8 – 8.2||7.3 – 8.5|
|Blue tiger shrimp||7.2 – 7.4||6.5 – 8.0|
|Blue bolt shrimp||6.0 – 6.8||5.5 – 7.2|
|Vampire shrimp||6.8 – 7.2||6.0 – 8.0|
How does pH Affect Shrimp
Sub-optimal pH has a number of adverse effects on our shrimp.
- If pH changes significantly, it can make shrimp shocked, weakened and stop eating.
- In high or low pH extends for a long time, it will make shrimp grow slowly, stunting growth and susceptible to diseases.
- It can cause stress, less survivals, low reproduction (or eggs loss) and leads to poor growth.
Signs of sub-optimal pH include:
- increase mucus on the gill surfaces,
- black gill disease,
- damage to the eye lens,
- abnormal swimming behavior,
- loose shell, soft shell or too hard shell – molting problems for the shrimp.
- irregularity in molt.
The low pH levels will cause the shell of shrimp to become soft. This is due to the shell of the shrimp being composed of calcium carbonate which reacts with acid. High pH may also increase the toxicity of other substances. For example, the toxicity of ammonia is ten times more severe at a pH of 8 than it is at pH 7. It is directly toxic to aquatic life when it appears in alkaline conditions.
pH and kH Relation in Shrimp Tank
The aquarium pH is directly related to carbonate hardness (kH) levels in the aquarium. kH is the buffer that helps hold the pH stable. Therefore, if you are having a pH problem or your pH is dropping regularly you probably have a low to non-existent kH level. At the same time, high kH will not allow you to lower pH, when you need it.
So, it is a good idea to determine also your carbonate hardness (kH) level first.
How to measure pH
API is one of the best pH test kits (link to check the price on Amazon). It has recommended itself very well and I prefer it.
- Fill the test tube to the 5ml line.
- Add 3 drops of pH test solution, and then invert the test tube to mix the solution.
- Match the solution to the color card.
Tip: If you have a hard time seeing the colors when testing the water, hold it against a white piece of paper.
Tip # 2: Make a list of all your measurements. You will be able to track all the changes in your tank to see if it maintaining its stability.
Lower pH in Shrimp Tank
I would like to start off by repeating that when dealing with pH issues it is very important not to raise or lower pH too fast in your shrimp tanks. You generally do not want to go more than about half a degree in any 12 to 24 hour period so if you have a long way to raise or lower your pH try to do it over a period of days.
Note: do not forget to acclimatize new shrimp before putting them in the tank.
1. Reverse osmosis water
The easiest and safest method is using an RO system in shrimp tanks. Reverse osmosis water is almost free of minerals and can be used to soften your tap water. You will have to use shrimp re-mineralizers during water changes. Remineralizers add all necessary minerals into the water that shrimp need to survive and thrive.
2. Distilled water
Basically, for our goals, distilled water is almost the same as RO water. Highly-purified water (distilled, reverse-osmosis, other highly-filtered) has a TDS close to 0. You will have to use shrimp remineralizers as well.
You need a buffering substrate for that (ADA Amazonia aqua soil, Fluval Plant and Shrimp Stratum, Akadama-Bonsai soil, Shrimp king soil, Brightwell etc). It will allow you to decrease your water pH for a long time (1-2 years).
It is a very cheap way to affect your pH. However, do not expect miracles. If your kH is high, driftwood will not help you much. Keep in mind, that driftwood releases tannins, which can turn your water like almost a tea color.
5. Cholla wood
Again, it has almost the same effect as driftwood. Check the price.
Note: In addition, your shrimp will love it! It is great to create mini caves for the shrimp to hide. When cholla wood breaks down a layer of biofilm forms on it. This biofilm just so happens to be one of your shrimp favorite foods.
Technically, it is a form of chemical filtration because it serves almost the same purpose as carbon (However, carbon does not lower your pH). Peat brings down pH and hardness. It also adds tannins to your shrimp tank.
Sometimes, aquarists add peat moss as a layer underneath the substrate. It will help lower the pH for you but if you are new to shrimp keeping hobby, I would not advise doing that.
You can put some peat moss in a nylon bag and *add it in a filter or just hang it in the tank.
*Warning: peat moss will lower the pH of the water even faster than driftwood. That is why, for small tanks, it is not recommended to filter with peat, as it is hard to control.
Note: Make sure it is free of fertilizer and other chemicals.
7. Chemical (pH buffer)
This is a great way for beginners. Mix the pH buffer with tap water or to salt them up by using products to get parameters you want to. Link to check the price.
Tip: Measure your pH before you do a water change and after that.
8. Lemon juice or vinegar
Add a few drops of lemon juice or vinegar. Then check the pH level. If it is still high, add a few more drops, and then check the pH again. Do this slowly so that your shrimp can adjust to the change in pH levels. You do not want to shock them.
Note: 1 mL of distilled white vinegar per gallon of tank water to initially reduce pH by about 0.3 units.
Warning: Be very careful if you are adding vinegar to lower your pH. It causes CO2 to skyrocket in a very short period of time, causing bacteria bloom. In addition, it is not going to stay low. It is a short-term solution and you will have to keep adding it.
Lemon juice contains sugar. Bacteria love sugar so you will have a bacterial bloom as well. It can lead to depletion of oxygen in your shrimp tank. Therefore, be very careful if you decide to use this method. Also, your shrimp tank should have good aeration.
All in all, personally, I would resort to this method only in case of emergency (too many side-effects).
9. Almond leaves, oak leaves etc.
Actually, any leaves will lower your pH because any decaying plant matter is going to have tannins. However, besides lowering pH, almond leaves are very beneficial for the shrimp. It is a nice source of extra food form them. In addition, almond leaves have antifungal and antibacterial properties. All shrimp really like it.
Keep in mind that leaves will not change pH if your kH is too high.
10. Carbon Dioxide (CO2)
One of the most used ways to lower the pH, although this is one of the least good ways to do so (in my opinion). Carbon Dioxide helps the plants to grow (fertilizer). It also bonds with the water creating carbonic acid. This acid lowers the pH but has no effect on hardness.
Note: Be very careful as overdoses of CO2 (link to check the price on Amazon) can cause major issues for the shrimp. In addition, it is a quite expensive way to reduce pH.
Nitrates will lower the pH. However, I seriously doubt that this method will suit anybody.
Increasing pH in Shrimp Tank
- Alkaline buffers will raise pH but will also raise your kH.
- pH buffers will increase only pH (for example, such as “pH up”). Keep in mind that, increasing pH without dealing with kH is kind of temporary fix. Nonetheless, if you do not need high kH it will be the better option.
3. Crushed coral and Crushed oyster shells
Coral and shells have a very high concentration of calcium (carbonate). Due to the high amount of salt, it can be dangerous to the shrimp. The problems with using crushed coral you cannot really control the process. Therefore, you have to be very careful not to add too much.
Limestone-based rock among other types will contain calcium carbonate which will work to raise the pH as well as GH in your tank. This is another natural method of raising pH and overall water hardness.
Note: Be careful. Do not add too much. A lot of limestone can increase the pH up to 8.3 point!
5. Ash / Woodash
Ash can also increase the pH. However, it contains too much phosphor and phosphates. So, it is not recommended.
6. Sodium Carbonate / Baking soda
Baking soda will raise the pH but it acts fast. The common recommendation is 1 teaspoon per 5 gallons. Due to the fact that baking soda is fast-acting, you should remove your shrimp or fish before adding it. The sudden change in pH levels will harm your shrimp.
Rocks that contain calcium are used to increase the pH in freshwater tanks. In order to know that the rocks contain calcium, you can test it by putting a few drops of vinegar on the rock. If it starts to foam, the rock contains calcium.
|I highly recommend to read my article “How to Supplement Shrimp and Snails with Calcium”.|
The pH regulation in shrimp tanks is an important component in shrimp keeping hobby. The pH depends, among other things, on the CO² contained in the water and on the carbonate hardness (kH).
If your water parameters meet requirements, it reduces a lot of stress for your shrimp making them much less likely to get sick or die.
Depending on the species, however, some shrimp species require acidic or alkaline water to get breeding. Ideal for an aquarium with shrimps from the Sulawesi Lakes, the pH is between 7.5 and 8.5. By contrast, in the case of Neocaridina and various Caridina species, a pH of 6.5-7.5 pH, Red Bee shrimp should be kept at a pH of 6.2-6.8.