diff --git a/Cargo.lock b/Cargo.lock
index bbe6059..94e4c9c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -31,6 +31,7 @@ dependencies = [
  "bittorrent_udp",
  "cli_helpers",
  "crossbeam-channel",
+ "hashbrown",
  "histogram",
  "indexmap",
  "mimalloc",
@@ -317,6 +318,16 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "hashbrown"
+version = "0.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "479e9d9a1a3f8c489868a935b557ab5710e3e223836da2ecd52901d88935cb56"
+dependencies = [
+ "ahash",
+ "autocfg",
+]
+
 [[package]]
 name = "hermit-abi"
 version = "0.1.10"
diff --git a/TODO.md b/TODO.md
index 9f42c89..ff18748 100644
--- a/TODO.md
+++ b/TODO.md
@@ -1,7 +1,7 @@
 # TODO
 
 ## aquatic
-* Use hashbrown HashMap for faster hasher (or try SeaHash?)
+* thread 'main' panicked at 'overflow when subtracting duration from instant', src/libstd/time.rs:374:9
 * Put connections and torrent in a struct behind a commong lock. Add
   functionality for checking if mutex is unlocked before quitting to
   collect requests from channel (try_recv) up to a limit.
diff --git a/aquatic/Cargo.toml b/aquatic/Cargo.toml
index 94e59ce..028bd5b 100644
--- a/aquatic/Cargo.toml
+++ b/aquatic/Cargo.toml
@@ -15,6 +15,7 @@ name = "aquatic"
 bittorrent_udp = { path = "../bittorrent_udp" }
 cli_helpers = { path = "../cli_helpers" }
 crossbeam-channel = "0.4"
+hashbrown = "0.7"
 histogram = "0.6"
 indexmap = "1"
 mimalloc = { version = "0.1", default-features = false }
diff --git a/aquatic/src/lib/common.rs b/aquatic/src/lib/common.rs
index 834579a..a119c98 100644
--- a/aquatic/src/lib/common.rs
+++ b/aquatic/src/lib/common.rs
@@ -1,10 +1,10 @@
-use std::collections::HashMap;
 use std::net::{SocketAddr, IpAddr};
 use std::sync::{Arc, atomic::AtomicUsize};
 use std::time::Instant;
 
-use parking_lot::Mutex;
+use hashbrown::HashMap;
 use indexmap::IndexMap;
+use parking_lot::Mutex;
 
 pub use bittorrent_udp::types::*;
 
diff --git a/aquatic/src/lib/handlers.rs b/aquatic/src/lib/handlers.rs
index 41fa3ed..702a931 100644
--- a/aquatic/src/lib/handlers.rs
+++ b/aquatic/src/lib/handlers.rs
@@ -3,7 +3,7 @@ use std::sync::atomic::Ordering;
 use std::time::{Duration, Instant};
 use std::vec::Drain;
 
-use parking_lot::{Mutex, MutexGuard};
+use parking_lot::MutexGuard;
 use crossbeam_channel::{Sender, Receiver};
 use rand::{SeedableRng, Rng, rngs::{SmallRng, StdRng}};