diff --git a/Gemfile.lock b/Gemfile.lock
index d00e819c..1b191914 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -123,7 +123,7 @@ GEM
     erubis (2.7.0)
     eventmachine (1.0.9.1)
     eventmachine (1.0.9.1-java)
-    excon (0.45.4)
+    excon (0.54.0)
     execjs (2.6.0)
     factory_girl (4.5.0)
       activesupport (>= 3.0.0)
diff --git a/lib/docker_client.rb b/lib/docker_client.rb
index 4672360f..a8bdf915 100644
--- a/lib/docker_client.rb
+++ b/lib/docker_client.rb
@@ -108,7 +108,7 @@ class DockerClient
     container.status = :created
     container
   rescue Docker::Error::NotFoundError => error
-    Rails.logger.info('create_container: Got Docker::Error::NotFoundError: ' + error.to_s)
+    Rails.logger.error('create_container: Got Docker::Error::NotFoundError: ' + error.to_s)
     destroy_container(container)
     #(tries += 1) <= RETRY_COUNT ? retry : raise(error)
   end
@@ -325,7 +325,7 @@ class DockerClient
   end
 
   def self.image_tags
-    Docker::Image.all.map { |image| image.info['RepoTags'] }.flatten.reject { |tag| tag.include?('<none>') }
+    Docker::Image.all.map { |image| image.info['RepoTags'] }.flatten.reject { |tag| tag.present? && tag.include?('<none>') }
   end
 
   def initialize(options = {})
@@ -390,8 +390,8 @@ class DockerClient
     Timeout.timeout(@execution_environment.permitted_execution_time.to_i) do
       #TODO: check phusion doku again if we need -i -t options here
       output = container.exec(['bash', '-c', command])
-      Rails.logger.info "output from container.exec"
-      Rails.logger.info output
+      Rails.logger.debug "output from container.exec"
+      Rails.logger.debug output
       result = {status: output[2] == 0 ? :ok : :failed, stdout: output[0].join.force_encoding('utf-8'), stderr: output[1].join.force_encoding('utf-8')}
     end
     # if we use pooling and recylce the containers, put it back. otherwise, destroy it.
diff --git a/lib/docker_container_pool.rb b/lib/docker_container_pool.rb
index 7f1f16fd..a2dc1a2e 100644
--- a/lib/docker_container_pool.rb
+++ b/lib/docker_container_pool.rb
@@ -7,7 +7,9 @@ class DockerContainerPool
   @containers = ThreadSafe::Hash[ExecutionEnvironment.all.map { |execution_environment| [execution_environment.id, ThreadSafe::Array.new] }]
   #as containers are not containing containers in use
   @all_containers = ThreadSafe::Hash[ExecutionEnvironment.all.map { |execution_environment| [execution_environment.id, ThreadSafe::Array.new] }]
+
   def self.clean_up
+    Rails.logger.info('Container Pool is now performing a cleanup. ')
     @refill_task.try(:shutdown)
     @all_containers.values.each do |containers|
       DockerClient.destroy_container(containers.shift) until containers.empty?