diff --git a/biomes/level1.lua b/biomes/level1.lua
index 1164593..55ee2e7 100644
--- a/biomes/level1.lua
+++ b/biomes/level1.lua
@@ -216,10 +216,10 @@ minetest.register_biome({
 	y_max = subsea_level,
 	heat_point = 50,
 	humidity_point = 100,
-	_subterrane_fill_node = c_water,
+	_subterrane_fill_node = c_air,
 	_subterrane_cave_fill_node = c_water,
 	_subterrane_floor_decor = level_1_underwater_floor,
-	_subterrane_mitigate_lava = false, -- no need to mitigate lava in a flooded cave, problem is self-solving
+	_subterrane_mitigate_lava = true,
 })
 
 minetest.register_biome({
@@ -300,7 +300,7 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_fill_node = c_water,
 	_subterrane_floor_decor = level_1_underwater_floor,
-	_subterrane_mitigate_lava = false, -- no need to mitigate lava in a flooded cave, problem is self-solving
+	_subterrane_mitigate_lava = true,
 })
 
 
@@ -327,7 +327,7 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_fill_node = c_water,
 	_subterrane_floor_decor = level_1_underwater_floor,
-	_subterrane_mitigate_lava = false, -- no need to mitigate lava in a flooded cave, problem is self-solving
+	_subterrane_mitigate_lava = true,
 })
 
 minetest.register_biome({
diff --git a/biomes/level2.lua b/biomes/level2.lua
index cf2e3e4..19f350d 100644
--- a/biomes/level2.lua
+++ b/biomes/level2.lua
@@ -264,6 +264,8 @@ local level_2_underwater_floor = function(area, data, ai, vi, bi, param2_data)
 		return
 	end
 	data[bi] = c_dirt
+	if data[vi] == c_air then data[vi] = c_water end
+	if data[ai] == c_air then data[ai] = c_water end
 end
 
 local level_2_cave_floor = function(area, data, ai, vi, bi, param2_data)
@@ -312,7 +314,7 @@ minetest.register_biome({
 	y_max = subsea_level,
 	heat_point = 50,
 	humidity_point = 90,
-	_subterrane_fill_node = c_water,
+	_subterrane_fill_node = c_air,
 	_subterrane_cave_fill_node = c_water,
 	_subterrane_floor_decor = level_2_underwater_floor,
 	_subterrane_mitigate_lava = false,
diff --git a/biomes/level3.lua b/biomes/level3.lua
index 767e8e8..6af087e 100644
--- a/biomes/level3.lua
+++ b/biomes/level3.lua
@@ -104,6 +104,8 @@ local level_3_underwater_floor = function(area, data, ai, vi, bi, param2_data)
 		return
 	end
 	data[bi] = c_dirt
+	if data[vi] == c_air then data[vi] = c_water end
+	if data[ai] == c_air then data[ai] = c_water end
 end
 
 local level_3_dry_ceiling = function(area, data, ai, vi, bi, param2_data)
@@ -322,7 +324,7 @@ minetest.register_biome({
 	y_max = subsea_level,
 	heat_point = 50,
 	humidity_point = 90,
-	_subterrane_fill_node = c_water,
+	_subterrane_fill_node = c_air,
 	_subterrane_cave_fill_node = c_water,
 	_subterrane_floor_decor = level_3_underwater_floor,
 })
diff --git a/biomes/sunless_sea.lua b/biomes/sunless_sea.lua
index 0e4d904..c92e03e 100644
--- a/biomes/sunless_sea.lua
+++ b/biomes/sunless_sea.lua
@@ -14,9 +14,6 @@ local c_glow_water = minetest.get_content_id("dfcaverns:glow_water_source")
 
 -------------------------------------------------------------------------------------------
 
-minetest.debug(dfcaverns.config.sunless_sea_min)
-minetest.debug(dfcaverns.config.sunless_sea_level)
-
 local sunless_sea_underwater_floor = function(area, data, ai, vi, bi, param2_data)
 	if data[bi] ~= c_stone then
 		return