diff --git a/docs/installation.rst b/docs/installation.rst
index 6846674f..ca7ca767 100644
--- a/docs/installation.rst
+++ b/docs/installation.rst
@@ -9,11 +9,14 @@ Installation from PyPI
 ----------------------
 
 .. important::
-   Before installing ``species``, it is required to separately install ``cython``:
+   Before installing ``species``, it is required to separately install ``cython`` and ``ultranest``:
 
    .. code-block:: console
 
        $ pip install cython
+       $ pip install ultranest
+
+   The installation of ``ultranest`` has caused problems on some machines. It is possible to skip the installation of that package, in which case it is still possible to use ``species``, apart from the functionalities that rely on `UltraNest <https://johannesbuchner.github.io/UltraNest/index.html>`_.
 
 The ``species`` toolkit can be installed with the `pip package manager <https://packaging.python.org/tutorials/installing-packages/>`_:
 
diff --git a/species/analysis/fit_model.py b/species/analysis/fit_model.py
index fb5fe5e7..0efece3b 100644
--- a/species/analysis/fit_model.py
+++ b/species/analysis/fit_model.py
@@ -525,7 +525,7 @@ def __init__(
                  automatically included in the fit, as it sets the
                  weight of the two components. Modeling blended data
                  is only supported by ``run_ultranest`` and
-                 ``run_multinest``. 
+                 ``run_multinest``.
 
             Blackbody parameters (with ``model='planck'``):
 
diff --git a/species/data/database.py b/species/data/database.py
index 3980cd8c..a7b63e13 100644
--- a/species/data/database.py
+++ b/species/data/database.py
@@ -3166,7 +3166,7 @@ def get_retrieval_spectra(
                 temp_nodes = dset.attrs["temp_nodes"]
 
         else:
-            # For backward compatibility 
+            # For backward compatibility
             temp_nodes = None
 
         # Get distance
diff --git a/species/data/model_spectra.py b/species/data/model_spectra.py
index 155a1a06..631aa4f4 100644
--- a/species/data/model_spectra.py
+++ b/species/data/model_spectra.py
@@ -169,7 +169,9 @@ def add_model_grid(
 
     else:
         wavelength = None
-        print(f"Wavelength range (um) = {model_info['wavelength range'][0]} - {model_info['wavelength range'][1]}")
+        print(f"Wavelength range (um) = "
+              f"{model_info['wavelength range'][0]} -"
+              f"{model_info['wavelength range'][1]}")
         print(f"Spectral resolution = {model_info['resolution']}")
 
     if teff_range is None: