GH and KH for shrimp aquariums: what are the ideal parameters for Caridina and Neocaridina?

GH and KH are among the most important parameters to understand when keeping aquarium shrimp.

They directly influence the mineral composition of the water, its stability, and the conditions in which Caridina and Neocaridina thrive.

But when you're just starting out, it is easy to confuse the two:

What is GH for? What is KH for? What values should you aim for with Caridina or Neocaridina?

In this Shrimpsfood guide, we will simply explain the difference between GH and KH, the values generally used, and, most importantly, how to interpret them correctly.

---

💧 What is GH in an aquarium?

GH, for General Hardness, corresponds to the total hardness of the water.

In the aquarium hobby, it mainly reflects the presence of certain dissolved minerals, including:

• calcium;
• magnesium;
• and other ions contributing to water hardness.

GH is generally expressed in:

°dGH

The higher the GH, the harder the water is considered to be.

Conversely, a low GH corresponds to softer and less mineralized water.

---

🦐 Why is GH important for shrimp?

Shrimp need a certain amount of minerals to properly carry out their biological functions.

Calcium and magnesium, in particular, contribute to the animal's overall mineral balance.

GH is therefore particularly important for:

• growth;
• exoskeleton formation;
• the molting process;
• reproduction;
• the overall maintenance of the colony.

An unsuitable GH can contribute to creating poor maintenance conditions, but GH should never be considered alone.

Conductivity, pH, KH, temperature, and water stability must also be taken into account.

---

🧪 What is KH?

KH, or carbonate hardness, is mainly linked to the presence of bicarbonates and carbonates in the water.

Its main role is very different from that of GH.

KH contributes to the buffering capacity of the water.

In other words, it helps the water resist rapid pH fluctuations.

Water with a relatively high KH generally has a higher buffering capacity.

Conversely, when the KH is very low or close to zero, the pH can be much more influenced by other elements in the aquarium, particularly an active substrate.

---

🔄 GH and KH: what is the difference?

These two parameters are often confused because both are expressed in degrees of hardness.

However, they measure different things.

---

📊 What GH and KH for Caridina and Neocaridina?

There is no single value that is valid for all shrimp.

The parameters depend specifically on:

• the species;
• the strain;
• the original breeding facility;
• the type of substrate;
• the salts used;
• the maintenance method.

However, the following values can be used as indicative orders of magnitude.

---

🔴 GH and KH for Caridina

Many Caridina, such as:

• Crystal Red;
• Crystal Black;
• Taiwan Bee;
• Blue Bolt;
• Pinto;

are often kept in soft and relatively low-mineralized water.

The commonly used method consists of starting with RO (reverse osmosis) water and then remineralizing it with suitable salts.

The goal is generally:

• a moderate GH;
• a very low or zero KH;
• a slightly acidic pH;
• controlled conductivity;
• an active substrate capable of influencing the parameters.

---

🔵 GH and KH for Neocaridina

Neocaridina are generally more tolerant regarding water hardness.

This includes, notably:

• Red Cherry;
• Bloody Mary;
• Blue Dream;
• Yellow Neon;
• Green Jade;
• Orange Sakura.

They are generally kept in water that is more mineralized than Taiwan Bee-type Caridina.

A GH around 6 to 10 and a KH around 2 to 6 often constitute reasonable starting values.

But again, it is important to know the parameters in which the shrimp were raised.

---

🪨 Why is KH often close to zero with an active substrate?

Active substrate is widely used in aquariums dedicated to Caridina.

It generally has the ability to influence water chemistry and maintain a rather acidic environment.

To function correctly, this type of substrate is generally paired with water that has a low KH.

When water with a high KH is introduced into an aquarium with an active substrate, the substrate must continuously fight against the buffering capacity of that water.

This can, in particular, gradually reduce the substrate's ability to maintain the desired parameters.

---

🧂 RO water and remineralizing salts

RO (reverse osmosis) water contains very few minerals.

It therefore constitutes a particularly practical base for preparing water suitable for shrimp.

Remineralizing salts are then added.

There are, notably, salts that are:

• GH+;
• GH/KH+.

The choice depends on the type of shrimp being kept.

For many Caridina

A GH+ salt is generally used to increase total hardness without significantly increasing the KH.

For Neocaridina

It is possible to use salts that increase both GH and KH, depending on the chosen maintenance method.

---

📈 What happens if the GH is too high?

A very high GH means the water contains a high concentration of certain minerals responsible for hardness.

A value that is too high relative to the needs of a strain can create unsuitable maintenance conditions.

It is, however, important not to modify the GH abruptly.

If your parameters need to be corrected, the adjustments must be made gradually.

---

📉 What happens if the GH is too low?

Conversely, insufficiently mineralized water may not provide enough minerals to the shrimp.

A very low GH can, in particular, be one of the parameters to check when observing:

• molting difficulties;
• abnormal growth;
• poor reproduction;
• a colony that seems less dynamic.

Be careful, however: these symptoms can have many other causes.

---

🦐 GH, minerals, and shrimp molting

GH is often associated with molting problems.

And for a good reason: molting requires an appropriate mineral balance.

But it would be incorrect to say:

"bad molting = GH too low"

Bad molting can also be linked to:

• an abrupt variation in parameters;
• a GH that is too high;
• poor mineral composition;
• an unbalanced diet;
• stress;
• poor water quality;
• water changes that are too large.

One must therefore always analyze all of the parameters.

---

⚡ What is the relationship between GH and conductivity?

GH and conductivity are often linked, but they do not measure the same thing.

When you add remineralizing salts to RO water, you generally increase:

• the GH;
• and the conductivity.

But there is no universal conversion like:

1 GH = X µS

Everything depends on the composition of the salts used.

---

🔄 GH, KH, and water changes

During a water change, it is preferable to avoid abruptly replacing the aquarium water with water that has a very different hardness.

Before each water change, it can be useful to check:

• the GH of the new water;
• the KH;
• the conductivity;
• the temperature.

The goal is to prepare water that is relatively close to the aquarium's usual parameters.

---

💦 Can you lower the GH with RO water?

Yes.

RO water contains very few minerals and can therefore allow for the gradual reduction of water hardness.

One must, however, avoid any abrupt modification.

If your GH is too high, proceed with gradual water changes using properly prepared water.

---

🧂 How to increase the GH?

The most controllable method is to use remineralizing salts suitable for shrimp.

It is preferable to prepare the water in a separate container before introducing it into the aquarium.

You can then control:

• the GH;
• the KH;
• the conductivity;
• the temperature.

Avoid modifying parameters abruptly directly in the aquarium.

---

🚫 Common mistakes with GH and KH

• ❌ confusing GH and KH;
• ❌ modifying parameters abruptly;
• ❌ seeking exactly the same parameters as another breeder without taking their method into account;
• ❌ using only conductivity without ever checking the GH;
• ❌ adding salts directly to the tank without preparation;
• ❌ using highly buffered water on an active substrate intended for Caridina;
• ❌ believing that a poor GH is the only possible cause of bad molting.

---

❓ Frequently asked questions about GH and KH

What GH for Caridina?

For many Crystal or Taiwan Bee-type Caridina, a GH around 4 to 6 °dGH is commonly used.

The value must, however, be adapted to the strain and the maintenance method.

What KH for Caridina?

For many Caridina raised on active substrate, a very low KH is generally sought, often close to 0 to 1 °dKH.

What GH for Neocaridina?

Neocaridina are often kept at around 6 to 10 °dGH.

What KH for Neocaridina?

A KH of around 2 to 6 °dKH is frequently encountered in Neocaridina aquariums.

Does GH influence molting?

Yes, water mineralization plays an important role, but molting problems cannot be explained by GH alone.

Is it possible to have a high GH and a low KH?

Yes. Both parameters measure different elements.

This is particularly possible with reverse osmosis water remineralized only with GH+ salts.

Does active substrate lower the KH?

Many active substrates used for Caridina interact with carbonates and help maintain a low KH and a more acidic pH.

---

✅ In summary

• ✅ GH mainly indicates general hardness;
• ✅ KH is linked to the buffering capacity of the water;
• ✅ Caridina are often kept with a moderate GH and a very low KH;
• ✅ Neocaridina generally tolerate harder water;
• ✅ GH is particularly important during molting;
• ✅ Conductivity is a useful addition to tracking GH;
• ✅ Stability remains more important than searching for a perfect number.

---

• Share Share on Facebook
• Tweet Tweet on Twitter