diff --git a/eco-core/core-plugin/src/main/java/com/willfp/reforges/effects/Effect.java b/eco-core/core-plugin/src/main/java/com/willfp/reforges/effects/Effect.java
index cdcd8d8..6634c44 100644
--- a/eco-core/core-plugin/src/main/java/com/willfp/reforges/effects/Effect.java
+++ b/eco-core/core-plugin/src/main/java/com/willfp/reforges/effects/Effect.java
@@ -62,8 +62,15 @@ protected UUID getUUID(final int index,
      * @param player The player.
      * @param config The config.
      */
-    public void handleEnabling(@NotNull final Player player,
-                               @NotNull final JSONConfig config) {
+    public final void handleEnabling(@NotNull final Player player,
+                                     @NotNull final JSONConfig config) {
+        PlayerEffectStack.pushEffect(player, this);
+
+        this.handleEnable(player, config);
+    }
+
+    protected void handleEnable(@NotNull final Player player,
+                                @NotNull final JSONConfig config) {
         // Override when needed.
     }
 
@@ -72,7 +79,13 @@ public void handleEnabling(@NotNull final Player player,
      *
      * @param player The player.
      */
-    public void handleDisabling(@NotNull final Player player) {
+    public final void handleDisabling(@NotNull final Player player) {
+        this.handleDisable(player);
+
+        PlayerEffectStack.popEffect(player, this);
+    }
+
+    protected void handleDisable(@NotNull final Player player) {
         // Override when needed.
     }
 
diff --git a/eco-core/core-plugin/src/main/kotlin/com/willfp/reforges/effects/PlayerEffectStack.kt b/eco-core/core-plugin/src/main/kotlin/com/willfp/reforges/effects/PlayerEffectStack.kt
new file mode 100644
index 0000000..62ddab2
--- /dev/null
+++ b/eco-core/core-plugin/src/main/kotlin/com/willfp/reforges/effects/PlayerEffectStack.kt
@@ -0,0 +1,29 @@
+@file:JvmName("PlayerEffectStack")
+
+package com.willfp.reforges.effects
+
+import org.bukkit.entity.Player
+import java.util.*
+
+private val effectStack = mutableMapOf<UUID, MutableMap<Effect, Int>>()
+
+fun Player.pushEffect(effect: Effect) {
+    val stack = effectStack[this.uniqueId] ?: mutableMapOf()
+    var amount = stack[effect] ?: 0
+    amount++
+    stack[effect] = amount
+    effectStack[this.uniqueId] = stack
+}
+
+fun Player.popEffect(effect: Effect) {
+    val stack = effectStack[this.uniqueId] ?: mutableMapOf()
+    var amount = stack[effect] ?: 0
+    amount--
+    stack[effect] = if (amount < 0) 0 else amount
+    effectStack[this.uniqueId] = stack
+}
+
+fun Player.getEffectAmount(effect: Effect): Int {
+    val stack = effectStack[this.uniqueId] ?: mutableMapOf()
+    return stack[effect] ?: 0
+}
diff --git a/eco-core/core-plugin/src/main/kotlin/com/willfp/reforges/effects/effects/EffectAttackSpeedMultiplier.kt b/eco-core/core-plugin/src/main/kotlin/com/willfp/reforges/effects/effects/EffectAttackSpeedMultiplier.kt
index d100ec1..f66c255 100644
--- a/eco-core/core-plugin/src/main/kotlin/com/willfp/reforges/effects/effects/EffectAttackSpeedMultiplier.kt
+++ b/eco-core/core-plugin/src/main/kotlin/com/willfp/reforges/effects/effects/EffectAttackSpeedMultiplier.kt
@@ -2,17 +2,17 @@ package com.willfp.reforges.effects.effects
 
 import com.willfp.eco.core.config.interfaces.JSONConfig
 import com.willfp.reforges.effects.Effect
+import com.willfp.reforges.effects.getEffectAmount
 import org.bukkit.attribute.Attribute
 import org.bukkit.attribute.AttributeModifier
 import org.bukkit.entity.Player
 
 class EffectAttackSpeedMultiplier : Effect("attack_speed_multiplier") {
-    override fun handleEnabling(player: Player,
-                                config: JSONConfig) {
+    override fun handleEnable(player: Player, config: JSONConfig) {
         val attribute = player.getAttribute(Attribute.GENERIC_ATTACK_SPEED) ?: return
         attribute.addModifier(
             AttributeModifier(
-                this.getUUID(1),
+                this.getUUID(player.getEffectAmount(this)),
                 this.id,
                 config.getDouble("multiplier") - 1,
                 AttributeModifier.Operation.MULTIPLY_SCALAR_1
@@ -20,11 +20,11 @@ class EffectAttackSpeedMultiplier : Effect("attack_speed_multiplier") {
         )
     }
 
-    override fun handleDisabling(player: Player) {
+    override fun handleDisable(player: Player) {
         val attribute = player.getAttribute(Attribute.GENERIC_ATTACK_SPEED) ?: return
         attribute.removeModifier(
             AttributeModifier(
-                this.getUUID(1),
+                this.getUUID(player.getEffectAmount(this)),
                 this.id,
                 0.0,
                 AttributeModifier.Operation.MULTIPLY_SCALAR_1
diff --git a/eco-core/core-plugin/src/main/kotlin/com/willfp/reforges/effects/effects/EffectKnockbackMultiplier.kt b/eco-core/core-plugin/src/main/kotlin/com/willfp/reforges/effects/effects/EffectKnockbackMultiplier.kt
index 07da49d..0f67c7a 100644
--- a/eco-core/core-plugin/src/main/kotlin/com/willfp/reforges/effects/effects/EffectKnockbackMultiplier.kt
+++ b/eco-core/core-plugin/src/main/kotlin/com/willfp/reforges/effects/effects/EffectKnockbackMultiplier.kt
@@ -2,17 +2,20 @@ package com.willfp.reforges.effects.effects
 
 import com.willfp.eco.core.config.interfaces.JSONConfig
 import com.willfp.reforges.effects.Effect
+import com.willfp.reforges.effects.getEffectAmount
 import org.bukkit.attribute.Attribute
 import org.bukkit.attribute.AttributeModifier
 import org.bukkit.entity.Player
 
 class EffectKnockbackMultiplier : Effect("knockback_multiplier") {
-    override fun handleEnabling(player: Player,
-                                config: JSONConfig) {
+    override fun handleEnable(
+        player: Player,
+        config: JSONConfig
+    ) {
         val attribute = player.getAttribute(Attribute.GENERIC_ATTACK_KNOCKBACK) ?: return
         attribute.addModifier(
             AttributeModifier(
-                this.getUUID(1),
+                this.getUUID(player.getEffectAmount(this)),
                 this.id,
                 config.getDouble("multiplier") - 1,
                 AttributeModifier.Operation.MULTIPLY_SCALAR_1
@@ -20,11 +23,11 @@ class EffectKnockbackMultiplier : Effect("knockback_multiplier") {
         )
     }
 
-    override fun handleDisabling(player: Player) {
+    override fun handleDisable(player: Player) {
         val attribute = player.getAttribute(Attribute.GENERIC_ATTACK_KNOCKBACK) ?: return
         attribute.removeModifier(
             AttributeModifier(
-                this.getUUID(1),
+                this.getUUID(player.getEffectAmount(this)),
                 this.id,
                 0.0,
                 AttributeModifier.Operation.MULTIPLY_SCALAR_1
diff --git a/eco-core/core-plugin/src/main/kotlin/com/willfp/reforges/effects/effects/EffectMovementSpeedMultiplier.kt b/eco-core/core-plugin/src/main/kotlin/com/willfp/reforges/effects/effects/EffectMovementSpeedMultiplier.kt
index 5e6fb16..a64132f 100644
--- a/eco-core/core-plugin/src/main/kotlin/com/willfp/reforges/effects/effects/EffectMovementSpeedMultiplier.kt
+++ b/eco-core/core-plugin/src/main/kotlin/com/willfp/reforges/effects/effects/EffectMovementSpeedMultiplier.kt
@@ -2,17 +2,20 @@ package com.willfp.reforges.effects.effects
 
 import com.willfp.eco.core.config.interfaces.JSONConfig
 import com.willfp.reforges.effects.Effect
+import com.willfp.reforges.effects.getEffectAmount
 import org.bukkit.attribute.Attribute
 import org.bukkit.attribute.AttributeModifier
 import org.bukkit.entity.Player
 
 class EffectMovementSpeedMultiplier : Effect("movement_speed_multiplier") {
-    override fun handleEnabling(player: Player,
-                                config: JSONConfig) {
+    override fun handleEnable(
+        player: Player,
+        config: JSONConfig
+    ) {
         val attribute = player.getAttribute(Attribute.GENERIC_MOVEMENT_SPEED) ?: return
         attribute.addModifier(
             AttributeModifier(
-                this.getUUID(1),
+                this.getUUID(player.getEffectAmount(this)),
                 this.id,
                 config.getDouble("multiplier") - 1,
                 AttributeModifier.Operation.MULTIPLY_SCALAR_1
@@ -20,11 +23,11 @@ class EffectMovementSpeedMultiplier : Effect("movement_speed_multiplier") {
         )
     }
 
-    override fun handleDisabling(player: Player) {
+    override fun handleDisable(player: Player) {
         val attribute = player.getAttribute(Attribute.GENERIC_MOVEMENT_SPEED) ?: return
         attribute.removeModifier(
             AttributeModifier(
-                this.getUUID(1),
+                this.getUUID(player.getEffectAmount(this)),
                 this.id,
                 0.0,
                 AttributeModifier.Operation.MULTIPLY_SCALAR_1