diff --git a/API.md b/API.md
index d3c0696..d2d512f 100644
--- a/API.md
+++ b/API.md
@@ -41,7 +41,12 @@ the new maximum.
 
 ### `mana.setregen(playername, value)`
 Sets the mana regeneration per mana tick of the player to `value`.
-Negative values are not permitted.
+Floating-point numbers are also permitted, in which the generation
+of 1 mana takes longer than 1 mana tick. I.e. `0.5`. means
+that 1 mana is generated every 2 mana ticks. A negative value means the
+player loses mana.
+
+
 The length of one “mana tick” is specified as the server-wide setting
 `mana_default_regen` in seconds.
 
diff --git a/README.txt b/README.txt
index f58b9d8..c06f789 100644
--- a/README.txt
+++ b/README.txt
@@ -38,7 +38,7 @@ Configuration
 This mod can be configured with minetest.conf! The following settings are accepted:
 
 * `mana_default_max`: Initial max. mana given to new players. Default: `200`. This value must be non-negative.
-* `mana_default_regen`: Initial regenerated mana per “mana tick”. Default: `1`. This value must be non-negative.
+* `mana_default_regen`: Initial regenerated mana per “mana tick”. Default: `1`. This value can be a floating value. I.e. if the value is `0.5`, 1 mana is generated every two mana ticks (note that the player's mana amount is still a whole number). This value can be negative, in which case the player will lose mana.
 * `mana_regen_timer`: The length of a “mana tick” in seconds. Each player will get his/her mana increased by the current
   regen value per mana tick. Default: `0.2`. This value must be positive, also try to avoid very small values
   as those could probably stress your machine a lot.