diff --git a/app/controllers/favorite_groups_controller.rb b/app/controllers/favorite_groups_controller.rb
index 2df12890f..9ffd97cf2 100644
--- a/app/controllers/favorite_groups_controller.rb
+++ b/app/controllers/favorite_groups_controller.rb
@@ -8,9 +8,12 @@ class FavoriteGroupsController < ApplicationController
   end
 
   def show
+    limit = params[:limit].presence || CurrentUser.user.per_page
+
     @current_item = @favorite_group = FavoriteGroup.find(params[:id])
     check_read_privilege(@favorite_group)
-    @post_set = PostSets::FavoriteGroup.new(@favorite_group, params[:page])
+    @posts = @favorite_group.posts.paginate(params[:page], limit: limit, count: @favorite_group.post_count)
+
     respond_with(@favorite_group)
   end
 
@@ -52,7 +55,7 @@ class FavoriteGroupsController < ApplicationController
     @favorite_group = FavoriteGroup.find(params[:id])
     check_write_privilege(@favorite_group)
     @post = Post.find(params[:post_id])
-    @favorite_group.add!(@post.id)
+    @favorite_group.add!(@post)
   end
 
   private
@@ -66,6 +69,6 @@ class FavoriteGroupsController < ApplicationController
   end
 
   def favgroup_params
-    params.fetch(:favorite_group, {}).permit(%i[name post_ids is_public], post_id_array: [])
+    params.fetch(:favorite_group, {}).permit(%i[name post_ids post_ids_string is_public], post_ids: [])
   end
 end
diff --git a/app/javascript/src/javascripts/posts.js.erb b/app/javascript/src/javascripts/posts.js.erb
index bbce80f17..58ce1fb80 100644
--- a/app/javascript/src/javascripts/posts.js.erb
+++ b/app/javascript/src/javascripts/posts.js.erb
@@ -193,7 +193,7 @@ Post.nav_prev = function(e) {
   } else if ($(".paginator a[rel~=prev]").length) {
     location.href = $("a[rel~=prev]").attr("href");
   } else {
-    href = $("#pool-nav li.pool-selected-true a[rel~=prev], #favgroup-nav a.active[rel~=prev]").attr("href");
+    href = $("#pool-nav li[data-selected=true] a[rel=prev], #favgroup-nav li[data-selected=true] a[rel=prev]").attr("href");
     if (href) {
       location.href = href;
     }
@@ -211,7 +211,7 @@ Post.nav_next = function(e) {
   } else if ($(".paginator a[rel~=next]").length) {
     location.href = $(".paginator a[rel~=next]").attr("href");
   } else {
-    href = $("#pool-nav li.pool-selected-true a[rel~=next], #favgroup-nav a.active[rel~=next]").attr("href");
+    href = $("#pool-nav li[data-selected=true] a[rel=next], #favgroup-nav li[data-selected=true] a[rel=next]").attr("href");
     if (href) {
       location.href = href;
     }
diff --git a/app/javascript/src/styles/specific/posts.scss b/app/javascript/src/styles/specific/posts.scss
index bf6336b71..fdbb5ac33 100644
--- a/app/javascript/src/styles/specific/posts.scss
+++ b/app/javascript/src/styles/specific/posts.scss
@@ -316,10 +316,6 @@ div#c-posts {
   }
 
   div#a-show {
-    .active, .pool-selected-true {
-      font-weight: bold;
-    }
-
     #post-info-source {
       word-break: break-all;
     }
@@ -377,6 +373,10 @@ div#c-posts {
         text-align: center;
         padding: 0 5.5em;
 
+        &[data-selected="true"] {
+          font-weight: bold;
+        }
+
         .prev {
           position: absolute;
           left: 2em;
diff --git a/app/logical/post_query_builder.rb b/app/logical/post_query_builder.rb
index 83c2c07d5..c2b5fdc7f 100644
--- a/app/logical/post_query_builder.rb
+++ b/app/logical/post_query_builder.rb
@@ -450,24 +450,12 @@ class PostQueryBuilder
       relation = relation.joins("JOIN (#{pool_posts.to_sql}) pool_posts ON pool_posts.post_id = posts.id").order("pool_posts.pool_index ASC")
     end
 
-    if q[:favgroups_neg].present?
-      q[:favgroups_neg].each do |favgroup_rec|
-        favgroup_id = favgroup_rec.to_i
-        favgroup = FavoriteGroup.where("favorite_groups.id = ?", favgroup_id).first
-        if favgroup
-          relation = relation.where.not("posts.id": favgroup.post_id_array)
-        end
-      end
+    q[:favgroups_neg].to_a.each do |favgroup|
+      relation = relation.where.not("posts.id": favgroup.post_ids)
     end
 
-    if q[:favgroups].present?
-      q[:favgroups].each do |favgroup_rec|
-        favgroup_id = favgroup_rec.to_i
-        favgroup = FavoriteGroup.where("favorite_groups.id = ?", favgroup_id).first
-        if favgroup
-          relation = relation.where("posts.id": favgroup.post_id_array)
-        end
-      end
+    q[:favgroups].to_a.each do |favgroup|
+      relation = relation.where("posts.id": favgroup.post_ids)
     end
 
     if q[:upvote].present?
diff --git a/app/logical/post_sets/favorite_group.rb b/app/logical/post_sets/favorite_group.rb
deleted file mode 100644
index ea571ef70..000000000
--- a/app/logical/post_sets/favorite_group.rb
+++ /dev/null
@@ -1,7 +0,0 @@
-module PostSets
-  class FavoriteGroup < PostSets::Pool
-    def presenter
-      @presenter ||= PostSetPresenters::FavoriteGroup.new(self)
-    end
-  end
-end
diff --git a/app/logical/post_sets/pool.rb b/app/logical/post_sets/pool.rb
deleted file mode 100644
index 981412229..000000000
--- a/app/logical/post_sets/pool.rb
+++ /dev/null
@@ -1,60 +0,0 @@
-module PostSets
-  class Pool < PostSets::Base
-    module ActiveRecordExtension
-      attr_accessor :total_pages, :current_page
-    end
-
-    attr_reader :pool, :page
-
-    def initialize(pool, page = 1)
-      @pool = pool
-      @page = page
-    end
-
-    def offset
-      (current_page - 1) * limit
-    end
-
-    def limit
-      CurrentUser.user.per_page
-    end
-
-    def tag_array
-      ["pool:#{pool.id}"]
-    end
-
-    def posts
-      @posts ||= begin
-        x = pool.posts(:offset => offset, :limit => limit)
-        x.extend(ActiveRecordExtension)
-        x.total_pages = total_pages
-        x.current_page = current_page
-        x
-      end
-    end
-
-    def tag_string
-      tag_array.join("")
-    end
-
-    def humanized_tag_string
-      "pool:#{pool.pretty_name}"
-    end
-
-    def presenter
-      @presenter ||= PostSetPresenters::Pool.new(self)
-    end
-
-    def total_pages
-      (pool.post_count.to_f / limit).ceil
-    end
-
-    def size
-      posts.size
-    end
-
-    def current_page
-      [page.to_i, 1].max
-    end
-  end
-end
diff --git a/app/models/favorite_group.rb b/app/models/favorite_group.rb
index a13003253..cb16bee9a 100644
--- a/app/models/favorite_group.rb
+++ b/app/models/favorite_group.rb
@@ -1,15 +1,13 @@
-require 'ostruct'
-
 class FavoriteGroup < ApplicationRecord
   validates_uniqueness_of :name, :case_sensitive => false, :scope => :creator_id
   validates_format_of :name, :with => /\A[^,]+\Z/, :message => "cannot have commas"
   belongs_to_creator
-  before_validation :normalize_post_ids
   before_validation :normalize_name
   before_validation :strip_name
   validate :creator_can_create_favorite_groups, :on => :create
   validate :validate_number_of_posts
-  before_save :update_post_count
+
+  array_attribute :post_ids, parse: /\d+/, cast: :to_i
 
   module SearchMethods
     def for_creator(user_id)
@@ -17,8 +15,7 @@ class FavoriteGroup < ApplicationRecord
     end
 
     def for_post(post_id)
-      regexp = "(^#{post_id}$|^#{post_id} | #{post_id}$| #{post_id} )"
-      where("favorite_groups.post_ids ~ ?", regexp)
+      where_array_includes_any(:post_ids, [post_id])
     end
 
     def named(name)
@@ -47,7 +44,7 @@ class FavoriteGroup < ApplicationRecord
 
     def search(params)
       q = super
-      q = q.search_attributes(params, :name, :is_public, :post_count)
+      q = q.search_attributes(params, :name, :is_public, :post_ids)
 
       if params[:creator_id].present?
         user = User.find(params[:creator_id])
@@ -91,15 +88,11 @@ class FavoriteGroup < ApplicationRecord
   end
 
   def validate_number_of_posts
-    if post_id_array.size > 10_000
-      self.errors.add(:base, "Favorite groups can have up to 10,000 posts each")
+    if post_count > 10_000
+      errors[:base] << "Favorite groups can have up to 10,000 posts each"
     end
   end
 
-  def normalize_post_ids
-    self.post_ids = post_ids.scan(/\d+/).uniq.join(" ")
-  end
-
   def self.normalize_name(name)
     name.gsub(/[[:space:]]+/, "_")
   end
@@ -126,94 +119,49 @@ class FavoriteGroup < ApplicationRecord
     name.tr("_", " ")
   end
 
-  def posts(options = {})
-    offset = options[:offset] || 0
-    limit = options[:limit] || Danbooru.config.posts_per_page
-    slice = post_id_array.slice(offset, limit)
-    if slice&.any?
-      slice.map do |id|
-        Post.find(id)
-      rescue ActiveRecord::RecordNotFound
-        # swallow
-      end.compact
-    else
-      []
-    end
+  def posts
+    favgroup_posts = FavoriteGroup.where(id: id).joins("CROSS JOIN unnest(favorite_groups.post_ids) WITH ORDINALITY AS row(post_id, favgroup_index)").select(:post_id, :favgroup_index)
+    posts = Post.joins("JOIN (#{favgroup_posts.to_sql}) favgroup_posts ON favgroup_posts.post_id = posts.id").order("favgroup_posts.favgroup_index ASC")
   end
 
-  def post_id_array
-    @post_id_array ||= post_ids.scan(/\d+/).map(&:to_i)
-  end
-
-  def post_id_array=(array)
-    self.post_ids = array.join(" ")
-    clear_post_id_array
-  end
-
-  def post_id_array_was
-    @post_id_array_was ||= post_ids_was.scan(/\d+/).map(&:to_i)
-  end
-
-  def clear_post_id_array
-    @post_id_array = nil
-    @post_id_array_was = nil
-  end
-
-  def update_post_count
-    normalize_post_ids
-    clear_post_id_array
-    self.post_count = post_id_array.size
-  end
-
-  def add!(post_id)
+  def add!(post)
     with_lock do
-      post_id = post_id.id if post_id.is_a?(Post)
-      return if contains?(post_id)
-
-      clear_post_id_array
-      update(post_ids: add_number_to_string(post_id, post_ids))
+      return if contains?(post.id)
+      update!(post_ids: post_ids + [post.id])
     end
   end
 
-  def remove!(post_id)
+  def remove!(post)
     with_lock do
-      post_id = post_id.id if post_id.is_a?(Post)
-      return unless contains?(post_id)
-
-      clear_post_id_array
-      update(post_ids: remove_number_from_string(post_id, post_ids))
+      return unless contains?(post.id)
+      update!(post_ids: post_ids - [post.id])
     end
   end
 
-  def add_number_to_string(number, string)
-    "#{string} #{number}"
+  def post_count
+    post_ids.size
   end
 
-  def remove_number_from_string(number, string)
-    string.gsub(/(?:\A| )#{number}(?:\Z| )/, " ")
+  def first_post?(post_id)
+    post_id == post_ids.first
   end
 
-  def neighbors(post)
-    @neighbor_posts ||= begin
-      post_ids =~ /\A#{post.id} (\d+)|(\d+) #{post.id} (\d+)|(\d+) #{post.id}\Z/
-
-      if $2 && $3
-        OpenStruct.new(:previous => $2.to_i, :next => $3.to_i)
-      elsif $1
-        OpenStruct.new(:next => $1.to_i)
-      elsif $4
-        OpenStruct.new(:previous => $4.to_i)
-      else
-        OpenStruct.new
-      end
-    end
+  def last_post?(post_id)
+    post_id == post_ids.last
   end
 
-  def reload(options = {})
-    super
-    @neighbor_posts = nil
-    clear_post_id_array
-    self
+  def previous_post_id(post_id)
+    return nil if first_post?(post_id) || !contains?(post_id)
+
+    n = post_ids.index(post_id) - 1
+    post_ids[n]
+  end
+
+  def next_post_id(post_id)
+    return nil if last_post?(post_id) || !contains?(post_id)
+
+    n = post_ids.index(post_id) + 1
+    post_ids[n]
   end
 
   def last_page
@@ -221,7 +169,7 @@ class FavoriteGroup < ApplicationRecord
   end
 
   def contains?(post_id)
-    post_ids =~ /(?:\A| )#{post_id}(?:\Z| )/
+    post_ids.include?(post_id)
   end
 
   def editable_by?(user)
diff --git a/app/models/pool.rb b/app/models/pool.rb
index 652490d2d..e1873542d 100644
--- a/app/models/pool.rb
+++ b/app/models/pool.rb
@@ -34,15 +34,6 @@ class Pool < ApplicationRecord
       where("pools.category = ?", "collection")
     end
 
-    def series_first
-      order(Arel.sql("(case pools.category when 'series' then 0 else 1 end), pools.name"))
-    end
-
-    def selected_first(current_pool_id)
-      return all if current_pool_id.blank?
-      reorder(Arel.sql("(case pools.id when #{current_pool_id.to_i} then 0 else 1 end), pools.name"))
-    end
-
     def name_matches(name)
       name = normalize_name_for_search(name)
       name = "*#{name}*" unless name =~ /\*/
diff --git a/app/models/post.rb b/app/models/post.rb
index f7c736ae6..0704236b4 100644
--- a/app/models/post.rb
+++ b/app/models/post.rb
@@ -822,19 +822,19 @@ class Post < ApplicationRecord
 
         when /^-favgroup:(\d+)$/i
           favgroup = FavoriteGroup.where("id = ?", $1.to_i).for_creator(CurrentUser.user.id).first
-          favgroup&.remove!(id)
+          favgroup&.remove!(self)
 
         when /^-favgroup:(.+)$/i
           favgroup = FavoriteGroup.named($1).for_creator(CurrentUser.user.id).first
-          favgroup&.remove!(id)
+          favgroup&.remove!(self)
 
         when /^favgroup:(\d+)$/i
           favgroup = FavoriteGroup.where("id = ?", $1.to_i).for_creator(CurrentUser.user.id).first
-          favgroup&.add!(id)
+          favgroup&.add!(self)
 
         when /^favgroup:(.+)$/i
           favgroup = FavoriteGroup.named($1).for_creator(CurrentUser.user.id).first
-          favgroup&.add!(id)
+          favgroup&.add!(self)
 
         end
       end
@@ -962,21 +962,8 @@ class Post < ApplicationRecord
       ordered_users
     end
 
-    def favorite_groups(active_id = nil)
-      @favorite_groups ||= begin
-        groups = []
-
-        if active_id.present?
-          active_group = FavoriteGroup.where(:id => active_id.to_i).first
-          groups << active_group if active_group&.contains?(self.id)
-        end
-
-        groups += CurrentUser.user.favorite_groups.select do |favgroup|
-          favgroup.contains?(self.id)
-        end
-
-        groups.uniq
-      end
+    def favorite_groups
+      FavoriteGroup.for_post(id)
     end
 
     def remove_from_favorites
@@ -988,7 +975,7 @@ class Post < ApplicationRecord
 
     def remove_from_fav_groups
       FavoriteGroup.for_post(id).find_each do |favgroup|
-        favgroup.remove!(id)
+        favgroup.remove!(self)
       end
     end
   end
@@ -1008,7 +995,7 @@ class Post < ApplicationRecord
 
   module PoolMethods
     def pools
-      Pool.where("pools.post_ids && array[?]", id).series_first
+      Pool.where("pools.post_ids && array[?]", id)
     end
 
     def has_active_pools?
@@ -1804,7 +1791,6 @@ class Post < ApplicationRecord
     super
     reset_tag_array_cache
     @pools = nil
-    @favorite_groups = nil
     @tag_categories = nil
     @typed_tags = nil
     self
diff --git a/app/models/tag.rb b/app/models/tag.rb
index 55466ce01..4c47daad2 100644
--- a/app/models/tag.rb
+++ b/app/models/tag.rb
@@ -602,7 +602,7 @@ class Tag < ApplicationRecord
             end
 
             q[:favgroups_neg] ||= []
-            q[:favgroups_neg] << favgroup_id
+            q[:favgroups_neg] << favgroup
 
           when "favgroup"
             favgroup_id = FavoriteGroup.name_to_id(g2)
@@ -613,7 +613,7 @@ class Tag < ApplicationRecord
             end
 
             q[:favgroups] ||= []
-            q[:favgroups] << favgroup_id
+            q[:favgroups] << favgroup
 
           when "-fav"
             favuser = User.find_by_name(g2)
diff --git a/app/presenters/post_presenter.rb b/app/presenters/post_presenter.rb
index 430b2c33a..3980dc809 100644
--- a/app/presenters/post_presenter.rb
+++ b/app/presenters/post_presenter.rb
@@ -173,7 +173,7 @@ class PostPresenter < Presenter
   end
 
   def has_nav_links?(template)
-    has_sequential_navigation?(template.params) || @post.pools.undeleted.any? || @post.favorite_groups(active_id = template.params[:favgroup_id]).any?
+    has_sequential_navigation?(template.params) || @post.pools.undeleted.any? || CurrentUser.favorite_groups.for_post(@post.id).any?
   end
 
   def has_sequential_navigation?(params)
diff --git a/app/presenters/post_set_presenters/favorite_group.rb b/app/presenters/post_set_presenters/favorite_group.rb
deleted file mode 100644
index b2056f272..000000000
--- a/app/presenters/post_set_presenters/favorite_group.rb
+++ /dev/null
@@ -1,17 +0,0 @@
-module PostSetPresenters
-  class FavoriteGroup < PostSetPresenters::Pool
-    def post_previews_html(template)
-      html = ""
-
-      if posts.empty?
-        return template.render("post_sets/blank")
-      end
-
-      posts.each do |post|
-        html << PostPresenter.preview(post, :favgroup_id => post_set.pool.id, :show_deleted => true)
-      end
-
-      html.html_safe
-    end
-  end
-end
diff --git a/app/presenters/post_set_presenters/pool.rb b/app/presenters/post_set_presenters/pool.rb
deleted file mode 100644
index 1b0e312de..000000000
--- a/app/presenters/post_set_presenters/pool.rb
+++ /dev/null
@@ -1,24 +0,0 @@
-module PostSetPresenters
-  class Pool < Base
-    attr_reader :post_set
-    delegate :posts, :to => :post_set
-
-    def initialize(post_set)
-      @post_set = post_set
-    end
-
-    def post_previews_html(template)
-      html = ""
-
-      if posts.empty?
-        return template.render("post_sets/blank")
-      end
-
-      posts.each do |post|
-        html << PostPresenter.preview(post, :pool_id => post_set.pool.id)
-      end
-
-      html.html_safe
-    end
-  end
-end
diff --git a/app/views/favorite_group_orders/edit.html.erb b/app/views/favorite_group_orders/edit.html.erb
index d3a3099a2..460af7004 100644
--- a/app/views/favorite_group_orders/edit.html.erb
+++ b/app/views/favorite_group_orders/edit.html.erb
@@ -6,8 +6,8 @@
     <%= render "posts/partials/common/inline_blacklist" %>
 
     <ul id="sortable">
-      <% @favorite_group.posts(:limit => 1_000).each do |post| %>
-        <li class="ui-state-default" id="favorite_group[post_id_array]_<%= post.id %>">
+      <% @favorite_group.posts.limit(1_000).each do |post| %>
+        <li class="ui-state-default" id="favorite_group[post_ids]_<%= post.id %>">
           <%= PostPresenter.preview(post).presence || "Hidden: Post ##{post.id}" %>
         </li>
       <% end %>
diff --git a/app/views/favorite_groups/edit.html.erb b/app/views/favorite_groups/edit.html.erb
index e9adcf5d6..ac6e706bc 100644
--- a/app/views/favorite_groups/edit.html.erb
+++ b/app/views/favorite_groups/edit.html.erb
@@ -6,7 +6,7 @@
 
     <%= edit_form_for(@favorite_group) do |f| %>
       <%= f.input :name, :as => :string, :input_html => { :value => @favorite_group.pretty_name } %>
-      <%= f.input :post_ids, :label => "Posts" %>
+      <%= f.input :post_ids_string, label: "Posts", as: :text %>
       <%= f.input :is_public %>
       <%= f.button :submit, "Submit" %>
     <% end %>
diff --git a/app/views/favorite_groups/new.html.erb b/app/views/favorite_groups/new.html.erb
index 9d1f6c506..74dcbc771 100644
--- a/app/views/favorite_groups/new.html.erb
+++ b/app/views/favorite_groups/new.html.erb
@@ -6,7 +6,7 @@
 
     <%= edit_form_for(@favorite_group) do |f| %>
       <%= f.input :name, :as => :string, :required => true %>
-      <%= f.input :post_ids, :label => "Posts" %>
+      <%= f.input :post_ids_string, :label => "Posts" %>
       <%= f.button :submit, "Submit" %>
     <% end %>
   </div>
diff --git a/app/views/favorite_groups/show.html.erb b/app/views/favorite_groups/show.html.erb
index b8291b19a..4cbea79d7 100644
--- a/app/views/favorite_groups/show.html.erb
+++ b/app/views/favorite_groups/show.html.erb
@@ -4,6 +4,7 @@
       Favorite Group:
       <%= link_to @favorite_group.pretty_name, posts_path(:tags => "favgroup:#{@favorite_group.id}") %>
     </h1>
+
     Creator: <%= link_to_user @favorite_group.creator %>
     <br>
     <br>
@@ -11,9 +12,13 @@
     <%= render "posts/partials/common/inline_blacklist" %>
 
     <section>
-      <%= @post_set.presenter.post_previews_html(self) %>
+      <% if @favorite_group.post_count == 0 %>
+        <%= render "post_sets/blank" %>
+      <% else %>
+        <%= post_previews_html(@posts, favgroup_id: @favorite_group.id) %>
 
-      <%= numbered_paginator(@post_set) %>
+        <%= numbered_paginator(@posts) %>
+      <% end %>
     </section>
   </div>
 </div>
diff --git a/app/views/posts/partials/show/_favorite_groups.html.erb b/app/views/posts/partials/show/_favorite_groups.html.erb
index 59b33675d..fe20599bb 100644
--- a/app/views/posts/partials/show/_favorite_groups.html.erb
+++ b/app/views/posts/partials/show/_favorite_groups.html.erb
@@ -1,25 +1,34 @@
 <div id="favgroup-nav">
   <ul>
-    <% post.favorite_groups(active_id=params[:favgroup_id]).each do |favgroup| %>
-      <li>
-        <% klass = "active" if favgroup.id == params[:favgroup_id].to_i %>
+    <% favgroups = favgroups.sort_by { |favgroup| [(favgroup.id == params[:favgroup_id].to_i) ? 0 : 1, favgroup.name] } %>
+    <% favgroups.each do |favgroup| %>
+      <% selected = favgroup.id == params[:favgroup_id].to_i %>
 
-        <% if favgroup.neighbors(post).previous %>
-          <%= link_to("&lsaquo;&thinsp;prev".html_safe, post_path(favgroup.neighbors(post).previous, :favgroup_id => favgroup.id), :rel => "prev", :class => "prev #{klass}") %>
-        <% else %>
-          <span class="prev">&lsaquo;&thinsp;prev</span>
-        <% end %>
-
-        <span class="favgroup-name <%= klass %>">
-          <%= link_to("Favorite group: #{favgroup.pretty_name}", favorite_group_path(favgroup)) %>
+      <%= tag.li id: "nav-link-for-favgroup-#{favgroup.id}", "data-selected": selected do %>
+        <span class="first">
+          <%= link_to_unless favgroup.first_post?(post.id), "«", post_path(favgroup.post_ids.first, favgroup_id: favgroup.id) %>
         </span>
 
-        <% if favgroup.neighbors(post).next %>
-          <%= link_to("next&thinsp;&rsaquo;".html_safe, post_path(favgroup.neighbors(post).next, :favgroup_id => favgroup.id), :rel => "next", :class => "next #{klass}") %>
-        <% else %>
-          <span class="next">next&thinsp;&rsaquo;</span>
+        <% favgroup.previous_post_id(post.id).tap do |previous_post_id| %>
+          <span class="prev">
+            <%= link_to_if previous_post_id, "‹ prev", post_path(previous_post_id.to_i, favgroup_id: favgroup.id), rel: ("prev" if selected) %>
+          </span>
         <% end %>
-      </li>
+
+        <span class="favgroup-name">
+          <%= link_to "Favorite group: #{favgroup.pretty_name}", favgroup %>
+        </span>
+
+        <% favgroup.next_post_id(post.id).tap do |next_post_id| %>
+          <span class="next">
+            <%= link_to_if next_post_id, "next ›", post_path(next_post_id.to_i, favgroup_id: favgroup.id), rel: ("next" if selected) %>
+          </span>
+        <% end %>
+
+        <span class="last">
+          <%= link_to_unless favgroup.last_post?(post.id), "»", post_path(favgroup.post_ids.last, favgroup_id: favgroup.id) %>
+        </span>
+      <% end %>
     <% end %>
   </ul>
 </div>
diff --git a/app/views/posts/partials/show/_nav_links.html.erb b/app/views/posts/partials/show/_nav_links.html.erb
index 10c4f0b94..78a9da7c2 100644
--- a/app/views/posts/partials/show/_nav_links.html.erb
+++ b/app/views/posts/partials/show/_nav_links.html.erb
@@ -5,11 +5,11 @@
     <% end %>
 
     <% if post.pools.undeleted.present? %>
-      <%= render "posts/partials/show/pool_list", post: post, pools: post.pools.undeleted.selected_first(params[:pool_id]) %>
+      <%= render "posts/partials/show/pool_list", post: post, pools: post.pools.undeleted %>
     <% end %>
 
-    <% if post.favorite_groups(active_id=params[:favgroup_id]).any? %>
-      <%= render "posts/partials/show/favorite_groups", :post => post %>
+    <% if CurrentUser.user.favorite_groups.for_post(post.id).present? %>
+      <%= render "posts/partials/show/favorite_groups", post: post, favgroups: CurrentUser.user.favorite_groups.for_post(post.id) %>
     <% end %>
   </div>
 <% end %>
diff --git a/app/views/posts/partials/show/_pool_list.html.erb b/app/views/posts/partials/show/_pool_list.html.erb
index 04edc82a2..20e6dca7a 100644
--- a/app/views/posts/partials/show/_pool_list.html.erb
+++ b/app/views/posts/partials/show/_pool_list.html.erb
@@ -1,5 +1,6 @@
 <div id="pool-nav">
   <ul>
+    <% pools = pools.sort_by { |pool| [is_pool_selected?(pool) ? 0 : 1, pool.is_series? ? 0 : 1, pool.name] } %>
     <% pools.each do |pool| %>
       <%= render "posts/partials/show/pool_list_item", pool: pool, post: post, selected: is_pool_selected?(pool) %>
     <% end %>
diff --git a/app/views/posts/partials/show/_pool_list_item.html.erb b/app/views/posts/partials/show/_pool_list_item.html.erb
index 621a7e3e8..d9eb82a8e 100644
--- a/app/views/posts/partials/show/_pool_list_item.html.erb
+++ b/app/views/posts/partials/show/_pool_list_item.html.erb
@@ -1,4 +1,4 @@
-<%= content_tag :li, id: "nav-link-for-pool-#{pool.id}", class: "pool-category-#{pool.category} pool-selected-#{selected}" do -%>
+<%= tag.li id: "nav-link-for-pool-#{pool.id}", class: "pool-category-#{pool.category}", "data-selected": selected do -%>
   <% if !pool.first_post?(post.id) && pool.post_ids.first -%>
     <%= link_to("&laquo;".html_safe, post_path(pool.post_ids.first, pool_id: pool.id), class: "first", title: "to page 1") %>
   <% else -%>
diff --git a/db/migrate/20200115010442_change_post_ids_to_array_on_favorite_groups.rb b/db/migrate/20200115010442_change_post_ids_to_array_on_favorite_groups.rb
new file mode 100644
index 000000000..d3f5a6589
--- /dev/null
+++ b/db/migrate/20200115010442_change_post_ids_to_array_on_favorite_groups.rb
@@ -0,0 +1,23 @@
+class ChangePostIdsToArrayOnFavoriteGroups < ActiveRecord::Migration[6.0]
+  def up
+    execute "set statement_timeout = 0"
+
+    change_column_default :favorite_groups, :post_ids, nil
+    change_column :favorite_groups, :post_ids, "integer[]", using: "string_to_array(post_ids, ' ')::integer[]"
+    change_column_default :favorite_groups, :post_ids, "{}"
+    add_index :favorite_groups, :post_ids, using: :gin
+
+    remove_column :favorite_groups, :post_count
+  end
+
+  def down
+    execute "set statement_timeout = 0"
+
+    remove_index :favorite_groups, :post_ids
+    change_column_default :favorite_groups, :post_ids, nil
+    change_column :favorite_groups, :post_ids, :text, using: "array_to_string(post_ids, ' ')"
+    change_column_default :favorite_groups, :post_ids, ""
+
+    add_column :favorite_groups, :post_count, :integer, default: 0, null: false
+  end
+end
diff --git a/db/structure.sql b/db/structure.sql
index 85592033e..f4b32785e 100644
--- a/db/structure.sql
+++ b/db/structure.sql
@@ -921,8 +921,7 @@ CREATE TABLE public.favorite_groups (
     id integer NOT NULL,
     name text NOT NULL,
     creator_id integer NOT NULL,
-    post_ids text DEFAULT ''::text NOT NULL,
-    post_count integer DEFAULT 0 NOT NULL,
+    post_ids integer[] DEFAULT '{}'::integer[] NOT NULL,
     created_at timestamp without time zone NOT NULL,
     updated_at timestamp without time zone NOT NULL,
     is_public boolean DEFAULT false NOT NULL
@@ -4975,6 +4974,13 @@ CREATE INDEX index_favorite_groups_on_creator_id ON public.favorite_groups USING
 CREATE INDEX index_favorite_groups_on_lower_name ON public.favorite_groups USING btree (lower(name));
 
 
+--
+-- Name: index_favorite_groups_on_post_ids; Type: INDEX; Schema: public; Owner: -
+--
+
+CREATE INDEX index_favorite_groups_on_post_ids ON public.favorite_groups USING gin (post_ids);
+
+
 --
 -- Name: index_favorites_0_on_post_id; Type: INDEX; Schema: public; Owner: -
 --
@@ -7400,6 +7406,7 @@ INSERT INTO "schema_migrations" (version) VALUES
 ('20191117200404'),
 ('20191119061018'),
 ('20191223032633'),
-('20200114204550');
+('20200114204550'),
+('20200115010442');
 
 
diff --git a/test/functional/favorite_groups_controller_test.rb b/test/functional/favorite_groups_controller_test.rb
index bbb85e511..c81ad37e6 100644
--- a/test/functional/favorite_groups_controller_test.rb
+++ b/test/functional/favorite_groups_controller_test.rb
@@ -33,7 +33,7 @@ class FavoriteGroupsControllerTest < ActionDispatch::IntegrationTest
     context "create action" do
       should "render" do
         post_auth favorite_groups_path, @user, params: { favorite_group: FactoryBot.attributes_for(:favorite_group) }
-        assert_redirected_to favorite_groups_path
+        assert_redirected_to favorite_group_path(FavoriteGroup.last)
       end
     end
 
@@ -47,11 +47,11 @@ class FavoriteGroupsControllerTest < ActionDispatch::IntegrationTest
     context "update action" do
       should "update posts" do
         @posts = create_list(:post, 2)
-        put_auth favorite_group_path(@favgroup), @user, params: { favorite_group: { name: "foo", post_id_array: @posts.map(&:id) } }
+        put_auth favorite_group_path(@favgroup), @user, params: { favorite_group: { name: "foo", post_ids: @posts.map(&:id).join(" ") } }
 
         assert_redirected_to @favgroup
         assert_equal("foo", @favgroup.reload.name)
-        assert_equal(@posts.map(&:id), @favgroup.post_id_array)
+        assert_equal(@posts.map(&:id), @favgroup.post_ids)
       end
     end
 
@@ -71,7 +71,7 @@ class FavoriteGroupsControllerTest < ActionDispatch::IntegrationTest
         put_auth add_post_favorite_group_path(@favgroup), @user, params: {post_id: @post.id, format: "js"}
         assert_response :success
         @favgroup.reload
-        assert_equal([@post.id], @favgroup.post_id_array)
+        assert_equal([@post.id], @favgroup.post_ids)
       end
     end
   end
diff --git a/test/unit/favorite_group_test.rb b/test/unit/favorite_group_test.rb
index 5f9e6dfd4..f141751d9 100644
--- a/test/unit/favorite_group_test.rb
+++ b/test/unit/favorite_group_test.rb
@@ -68,10 +68,10 @@ class FavoriteTest < ActiveSupport::TestCase
     end
 
     should "remove it from all favorite groups" do
-      assert_equal(@post.id.to_s, @fav_group.post_ids)
+      assert_equal([@post.id], @fav_group.post_ids)
       @post.expunge!
       @fav_group.reload
-      assert_equal("", @fav_group.post_ids)
+      assert_equal([], @fav_group.post_ids)
     end
   end
 end