diff --git a/src/components/blog/PostSorting.tsx b/src/components/blog/PostSorting.tsx
index d12c1c0..6aa302b 100644
--- a/src/components/blog/PostSorting.tsx
+++ b/src/components/blog/PostSorting.tsx
@@ -16,59 +16,38 @@ export interface PostSortingProps {
 }
 
 export default function PostSorting(props: PostSortingProps) {
-  // Build set of tags that are ALLOWED
-  const allowedTags = createMemo(() => {
-    // WHITELIST MODE: If 'include' param is present, only show posts with those tags
-    if (props.include) {
-      const includeList = props.include.split("|").filter(Boolean);
-      return new Set(includeList);
-    }
-
-    // BLACKLIST MODE: Filter out tags in 'filter' param
-    const filterList = props.filters?.split("|").filter(Boolean) || [];
-
-    // If no filters set, all tags are allowed
-    if (filterList.length === 0) {
-      return new Set(props.tags.map((t) => t.value.slice(1)));
-    }
-
-    // Build set of tags that are checked (allowed to show)
-    const allTags = new Set(props.tags.map((t) => t.value.slice(1)));
-    const filteredOutTags = new Set(filterList);
-
-    const allowed = new Set<string>();
-    allTags.forEach((tag) => {
-      if (!filteredOutTags.has(tag)) {
-        allowed.add(tag);
+  const filteredPosts = createMemo(() => {
+    // Build map of post_id -> tags for that post
+    const postTags = new Map<number, Set<string>>();
+    props.tags.forEach((tag) => {
+      if (!postTags.has(tag.post_id)) {
+        postTags.set(tag.post_id, new Set());
       }
+      // Tag values in DB have # prefix, remove it for comparison
+      const tagWithoutHash = tag.value.startsWith("#")
+        ? tag.value.slice(1)
+        : tag.value;
+      postTags.get(tag.post_id)!.add(tagWithoutHash);
     });
 
-    return allowed;
-  });
+    // WHITELIST MODE: Only show posts that have at least one of the included tags
+    if (props.include !== undefined) {
+      const includeList = props.include.split("|").filter(Boolean);
 
-  // Get posts that have at least one allowed tag
-  const filteredPosts = createMemo(() => {
-    const allowed = allowedTags();
+      // Empty whitelist means show nothing
+      if (includeList.length === 0) {
+        return [];
+      }
 
-    // In whitelist mode, only show posts with allowed tags
-    if (props.include) {
-      // Build map of post_id -> tags for that post
-      const postTags = new Map<number, Set<string>>();
-      props.tags.forEach((tag) => {
-        if (!postTags.has(tag.post_id)) {
-          postTags.set(tag.post_id, new Set());
-        }
-        postTags.get(tag.post_id)!.add(tag.value.slice(1));
-      });
+      const includeSet = new Set(includeList);
 
-      // Keep posts that have at least one allowed tag
       return props.posts.filter((post) => {
         const tags = postTags.get(post.id);
-        if (!tags) return false; // Post has no tags
+        if (!tags || tags.size === 0) return false;
 
-        // Check if post has at least one allowed tag
+        // Post must have at least one tag from the include list
         for (const tag of tags) {
-          if (allowed.has(tag)) {
+          if (includeSet.has(tag)) {
             return true;
           }
         }
@@ -76,38 +55,33 @@ export default function PostSorting(props: PostSortingProps) {
       });
     }
 
-    // In blacklist mode, show all posts if all tags are allowed
-    if (
-      allowed.size ===
-      props.tags
-        .map((t) => t.value.slice(1))
-        .filter((v, i, a) => a.indexOf(v) === i).length
-    ) {
-      return props.posts;
+    // BLACKLIST MODE: Hide posts that have ANY of the filtered tags
+    if (props.filters !== undefined) {
+      const filterList = props.filters.split("|").filter(Boolean);
+
+      // Empty blacklist means show everything
+      if (filterList.length === 0) {
+        return props.posts;
+      }
+
+      const filterSet = new Set(filterList);
+
+      return props.posts.filter((post) => {
+        const tags = postTags.get(post.id);
+        if (!tags || tags.size === 0) return true; // Show posts with no tags
+
+        // Post must NOT have any blacklisted tags
+        for (const tag of tags) {
+          if (filterSet.has(tag)) {
+            return false; // Hide this post
+          }
+        }
+        return true; // Show this post
+      });
     }
 
-    // Build map of post_id -> tags for that post
-    const postTags = new Map<number, Set<string>>();
-    props.tags.forEach((tag) => {
-      if (!postTags.has(tag.post_id)) {
-        postTags.set(tag.post_id, new Set());
-      }
-      postTags.get(tag.post_id)!.add(tag.value.slice(1));
-    });
-
-    // Keep posts that have at least one allowed tag
-    return props.posts.filter((post) => {
-      const tags = postTags.get(post.id);
-      if (!tags) return false; // Post has no tags
-
-      // Check if post has at least one allowed tag
-      for (const tag of tags) {
-        if (allowed.has(tag)) {
-          return true;
-        }
-      }
-      return false;
-    });
+    // No filters: show all posts
+    return props.posts;
   });
 
   const sortedPosts = createMemo(() => {
diff --git a/src/components/blog/PostSortingSelect.tsx b/src/components/blog/PostSortingSelect.tsx
index 9586ea7..a933477 100644
--- a/src/components/blog/PostSortingSelect.tsx
+++ b/src/components/blog/PostSortingSelect.tsx
@@ -1,4 +1,4 @@
-import { createSignal, createEffect, For, Show } from "solid-js";
+import { createSignal, For, Show } from "solid-js";
 import { useNavigate, useLocation, useSearchParams } from "@solidjs/router";
 import Check from "~/components/icons/Check";
 import UpDownArrows from "~/components/icons/UpDownArrows";
@@ -14,29 +14,25 @@ const sorting = [
 export interface PostSortingSelectProps {}
 
 export default function PostSortingSelect(props: PostSortingSelectProps) {
-  const [selected, setSelected] = createSignal(sorting[0]);
   const [isOpen, setIsOpen] = createSignal(false);
   const navigate = useNavigate();
   const location = useLocation();
   const [searchParams] = useSearchParams();
 
-  const currentFilters = () => searchParams.filter || null;
-  const currentInclude = () => searchParams.include || null;
-
-  createEffect(() => {
-    let newRoute = location.pathname + "?sort=" + selected().val;
-    if (currentFilters()) {
-      newRoute += "&filter=" + currentFilters();
-    }
-    if (currentInclude()) {
-      newRoute += "&include=" + currentInclude();
-    }
-    navigate(newRoute);
-  });
+  // Derive selected from URL params instead of local state
+  const selected = () => {
+    const sortParam = searchParams.sort || "newest";
+    return sorting.find((s) => s.val === sortParam) || sorting[0];
+  };
 
   const handleSelect = (sort: { val: string; label: string }) => {
-    setSelected(sort);
     setIsOpen(false);
+
+    // Build new URL preserving all existing params
+    const params = new URLSearchParams(searchParams as Record<string, string>);
+    params.set("sort", sort.val);
+
+    navigate(`${location.pathname}?${params.toString()}`);
   };
 
   return (
diff --git a/src/components/blog/TagSelector.tsx b/src/components/blog/TagSelector.tsx
index 45ca74d..b200827 100644
--- a/src/components/blog/TagSelector.tsx
+++ b/src/components/blog/TagSelector.tsx
@@ -24,18 +24,33 @@ export default function TagSelector(props: TagSelectorProps) {
   const location = useLocation();
   const [searchParams] = useSearchParams();
 
-  const currentSort = () => searchParams.sort || "";
   const currentFilters = () =>
     searchParams.filter?.split("|").filter(Boolean) || [];
   const currentInclude = () =>
     searchParams.include?.split("|").filter(Boolean) || [];
 
-  // Sync filter mode with URL params
+  // Get currently selected tags based on mode
+  const selectedTags = () => {
+    if (filterMode() === "whitelist") {
+      return currentInclude();
+    } else {
+      return currentFilters();
+    }
+  };
+
+  // Sync filter mode with URL params and ensure one is always present
   createEffect(() => {
-    if (searchParams.include) {
+    if ("include" in searchParams) {
       setFilterMode("whitelist");
-    } else if (searchParams.filter) {
+    } else if ("filter" in searchParams) {
       setFilterMode("blacklist");
+    } else {
+      // No filter param exists, default to blacklist mode with empty filter
+      const params = new URLSearchParams(
+        searchParams as Record<string, string>
+      );
+      params.set("filter", "");
+      navigate(`${location.pathname}?${params.toString()}`, { replace: true });
     }
   });
 
@@ -51,22 +66,15 @@ export default function TagSelector(props: TagSelectorProps) {
     Object.keys(props.tagMap).map((key) => key.slice(1))
   );
 
-  // In blacklist mode: checked = not filtered out
-  // In whitelist mode: checked = included in whitelist
+  // Check if a tag is currently selected
   const isTagChecked = (tag: string) => {
-    if (filterMode() === "whitelist") {
-      return currentInclude().includes(tag);
-    } else {
-      return !currentFilters().includes(tag);
-    }
+    return selectedTags().includes(tag);
   };
 
   const allChecked = createMemo(() => {
-    if (filterMode() === "whitelist") {
-      return currentInclude().length === allTagKeys().length;
-    } else {
-      return allTagKeys().every((tag) => !currentFilters().includes(tag));
-    }
+    return (
+      selectedTags().length === allTagKeys().length && allTagKeys().length > 0
+    );
   });
 
   const handleClickOutside = (e: MouseEvent) => {
@@ -94,84 +102,80 @@ export default function TagSelector(props: TagSelectorProps) {
   };
 
   const handleCheck = (tag: string, isChecked: boolean) => {
-    if (filterMode() === "whitelist") {
-      // Whitelist mode: manage include param
-      let newInclude: string[];
-      if (isChecked) {
-        // Add to whitelist
-        newInclude = [...currentInclude(), tag];
-      } else {
-        // Remove from whitelist
-        newInclude = currentInclude().filter((t) => t !== tag);
-      }
+    const currentSelected = selectedTags();
+    let newSelected: string[];
 
-      if (newInclude.length > 0) {
-        const includeStr = newInclude.map((t) => `#${t}`).join("|");
-        navigate(
-          `${location.pathname}?sort=${currentSort()}&include=${includeStr}`
-        );
-      } else {
-        // If no tags selected, clear whitelist
-        navigate(`${location.pathname}?sort=${currentSort()}`);
-      }
+    if (isChecked) {
+      // Add tag to selection
+      newSelected = [...currentSelected, tag];
     } else {
-      // Blacklist mode: manage filter param
-      if (isChecked) {
-        const newFilters = searchParams.filter?.replace(tag + "|", "");
-        if (newFilters && newFilters.length >= 1) {
-          navigate(
-            `${location.pathname}?sort=${currentSort()}&filter=${newFilters}`
-          );
-        } else {
-          navigate(`${location.pathname}?sort=${currentSort()}`);
-        }
-      } else {
-        const currentFiltersStr = searchParams.filter;
-        if (currentFiltersStr) {
-          const newFilters = currentFiltersStr + tag + "|";
-          navigate(
-            `${location.pathname}?sort=${currentSort()}&filter=${newFilters}`
-          );
-        } else {
-          navigate(`${location.pathname}?sort=${currentSort()}&filter=${tag}|`);
-        }
-      }
+      // Remove tag from selection
+      newSelected = currentSelected.filter((t) => t !== tag);
     }
+
+    // Build URL preserving all existing params
+    const params = new URLSearchParams(searchParams as Record<string, string>);
+    const paramName = filterMode() === "whitelist" ? "include" : "filter";
+    const otherParamName = filterMode() === "whitelist" ? "filter" : "include";
+
+    // Remove the other mode's param
+    params.delete(otherParamName);
+
+    if (newSelected.length > 0) {
+      const paramValue = newSelected.join("|");
+      params.set(paramName, paramValue);
+    } else {
+      // Keep empty param to preserve mode (especially important for whitelist)
+      params.set(paramName, "");
+    }
+
+    navigate(`${location.pathname}?${params.toString()}`);
   };
 
   const handleToggleAll = () => {
-    if (filterMode() === "whitelist") {
-      if (allChecked()) {
-        // Uncheck all: clear whitelist
-        navigate(`${location.pathname}?sort=${currentSort()}`);
-      } else {
-        // Check all: add all tags to whitelist
-        const allTags = allTagKeys()
-          .map((t) => `#${t}`)
-          .join("|");
-        navigate(
-          `${location.pathname}?sort=${currentSort()}&include=${allTags}`
-        );
-      }
+    const params = new URLSearchParams(searchParams as Record<string, string>);
+    const paramName = filterMode() === "whitelist" ? "include" : "filter";
+    const otherParamName = filterMode() === "whitelist" ? "filter" : "include";
+
+    // Remove the other mode's param
+    params.delete(otherParamName);
+
+    if (allChecked()) {
+      // Uncheck all: keep empty param to preserve mode
+      params.set(paramName, "");
     } else {
-      if (allChecked()) {
-        // Uncheck all: Build filter string with all tags
-        const allTags = allTagKeys().join("|") + "|";
-        navigate(
-          `${location.pathname}?sort=${currentSort()}&filter=${allTags}`
-        );
-      } else {
-        // Check all: Remove filter param
-        navigate(`${location.pathname}?sort=${currentSort()}`);
-      }
+      // Check all: select all tags
+      const allTags = allTagKeys().join("|");
+      params.set(paramName, allTags);
     }
+
+    navigate(`${location.pathname}?${params.toString()}`);
   };
 
   const toggleFilterMode = () => {
+    // Get current tags BEFORE changing mode
+    const currentSelected = selectedTags();
+
     const newMode = filterMode() === "whitelist" ? "blacklist" : "whitelist";
     setFilterMode(newMode);
-    // Clear all filters when switching modes
-    navigate(`${location.pathname}?sort=${currentSort()}`);
+
+    // Keep the same selected tags, just change the param name
+    const params = new URLSearchParams(searchParams as Record<string, string>);
+    const newParamName = newMode === "whitelist" ? "include" : "filter";
+    const oldParamName = newMode === "whitelist" ? "filter" : "include";
+
+    // Remove old param and set new one
+    params.delete(oldParamName);
+
+    if (currentSelected.length > 0) {
+      const paramValue = currentSelected.join("|");
+      params.set(newParamName, paramValue);
+    } else {
+      // Always keep the param, even if empty
+      params.set(newParamName, "");
+    }
+
+    navigate(`${location.pathname}?${params.toString()}`);
   };
 
   return (
@@ -209,8 +213,8 @@ export default function TagSelector(props: TagSelectorProps) {
             </div>
             <div class="text-subtext1 text-xs italic">
               {filterMode() === "whitelist"
-                ? "Check tags to show ONLY those posts"
-                : "Uncheck tags to HIDE those posts"}
+                ? "Check tags to show ONLY posts with those tags"
+                : "Check tags to HIDE posts with those tags"}
             </div>
           </div>
 
diff --git a/src/routes/blog/index.tsx b/src/routes/blog/index.tsx
index 9a53318..1b62a11 100644
--- a/src/routes/blog/index.tsx
+++ b/src/routes/blog/index.tsx
@@ -76,8 +76,10 @@ export default function BlogIndex() {
   const [searchParams] = useSearchParams();
 
   const sort = () => searchParams.sort || "newest";
-  const filters = () => searchParams.filter || "";
-  const include = () => searchParams.include || "";
+  const filters = () =>
+    "filter" in searchParams ? searchParams.filter : undefined;
+  const include = () =>
+    "include" in searchParams ? searchParams.include : undefined;
 
   const data = createAsync(() => getPosts(), { deferStream: true });