diff --git a/SAS/TMSS/backend/src/tmss/tmssapp/schemas/HBA-single-beam-observation-scheduling-unit-observation-strategy.json b/SAS/TMSS/backend/src/tmss/tmssapp/schemas/HBA-single-beam-observation-scheduling-unit-observation-strategy.json
index ad73745d513793c040b6f8cf53dc78f2f5081a56..9f7ce85e09e7d63412220fb0e5ae1d1caa03225a 100644
--- a/SAS/TMSS/backend/src/tmss/tmssapp/schemas/HBA-single-beam-observation-scheduling-unit-observation-strategy.json
+++ b/SAS/TMSS/backend/src/tmss/tmssapp/schemas/HBA-single-beam-observation-scheduling-unit-observation-strategy.json
@@ -22,13 +22,7 @@
           "autocorrelations":true
         },
         "demix":{
-          "sources":{
-              "CasA":"auto",
-              "CygA":"auto",
-              "HerA":"auto",
-              "TauA":"auto",
-              "VirA":"auto",
-              "HydraA":"auto" },
+          "sources": [],
           "time_steps":10,
           "ignore_target":false,
           "frequency_steps":64
@@ -116,13 +110,7 @@
           "autocorrelations":true
         },
         "demix":{
-          "sources":{
-              "CasA":"auto",
-              "CygA":"auto",
-              "HerA":"auto",
-              "TauA":"auto",
-              "VirA":"auto",
-              "HydraA":"auto" },
+          "sources": [],
           "time_steps":10,
           "ignore_target":false,
           "frequency_steps":64
@@ -147,13 +135,7 @@
           "autocorrelations":true
         },
         "demix":{
-          "sources":{
-              "CasA":"auto",
-              "CygA":"auto",
-              "HerA":"auto",
-              "TauA":"auto",
-              "VirA":"auto",
-              "HydraA":"auto" },
+          "sources": [],
           "time_steps":10,
           "ignore_target":false,
           "frequency_steps":64
diff --git a/SAS/TMSS/backend/src/tmss/tmssapp/schemas/LBA-survey-observation-scheduling-unit-observation-strategy.json b/SAS/TMSS/backend/src/tmss/tmssapp/schemas/LBA-survey-observation-scheduling-unit-observation-strategy.json
index 5e6ebb9d68a2b2f650cf0ace496a75bf0d6cfdf2..b609badce605465e2acd871383f4cb235e1d9ad1 100644
--- a/SAS/TMSS/backend/src/tmss/tmssapp/schemas/LBA-survey-observation-scheduling-unit-observation-strategy.json
+++ b/SAS/TMSS/backend/src/tmss/tmssapp/schemas/LBA-survey-observation-scheduling-unit-observation-strategy.json
@@ -514,13 +514,7 @@
           "autocorrelations":true
         },
         "demix":{
-          "sources":{
-              "CasA":"auto",
-              "CygA":"auto",
-              "HerA":"auto",
-              "TauA":"auto",
-              "VirA":"auto",
-              "HydraA":"auto" },
+          "sources": [],
           "time_steps":10,
           "ignore_target":false,
           "frequency_steps":64
@@ -542,13 +536,7 @@
           "autocorrelations":true
         },
         "demix":{
-          "sources":{
-              "CasA":"auto",
-              "CygA":"auto",
-              "HerA":"auto",
-              "TauA":"auto",
-              "VirA":"auto",
-              "HydraA":"auto" },
+          "sources": [],
           "time_steps":10,
           "ignore_target":false,
           "frequency_steps":64
@@ -570,13 +558,7 @@
           "autocorrelations":true
         },
         "demix":{
-          "sources":{
-              "CasA":"auto",
-              "CygA":"auto",
-              "HerA":"auto",
-              "TauA":"auto",
-              "VirA":"auto",
-              "HydraA":"auto" },
+          "sources": [],
           "time_steps":10,
           "ignore_target":false,
           "frequency_steps":64
@@ -598,13 +580,7 @@
           "autocorrelations":true
         },
         "demix":{
-          "sources":{
-              "CasA":"auto",
-              "CygA":"auto",
-              "HerA":"auto",
-              "TauA":"auto",
-              "VirA":"auto",
-              "HydraA":"auto" },
+          "sources": [],
           "time_steps":10,
           "ignore_target":false,
           "frequency_steps":64
diff --git a/SAS/TMSS/backend/src/tmss/tmssapp/schemas/LoTSS-observation-scheduling-unit-observation-strategy.json b/SAS/TMSS/backend/src/tmss/tmssapp/schemas/LoTSS-observation-scheduling-unit-observation-strategy.json
index 04e23c8cb95281e7633cc7e9a12bdb1b044e87bf..3fc1514896e0901425a11f4b1637a5043a45164a 100644
--- a/SAS/TMSS/backend/src/tmss/tmssapp/schemas/LoTSS-observation-scheduling-unit-observation-strategy.json
+++ b/SAS/TMSS/backend/src/tmss/tmssapp/schemas/LoTSS-observation-scheduling-unit-observation-strategy.json
@@ -22,13 +22,7 @@
           "autocorrelations":true
         },
         "demix":{
-          "sources":{
-              "CasA":"auto",
-              "CygA":"auto",
-              "HerA":"auto",
-              "TauA":"auto",
-              "VirA":"auto",
-              "HydraA":"auto" },
+          "sources": [],
           "time_steps":10,
           "ignore_target":false,
           "frequency_steps":64
@@ -53,13 +47,7 @@
           "autocorrelations":true
         },
         "demix":{
-          "sources":{
-              "CasA":"auto",
-              "CygA":"auto",
-              "HerA":"auto",
-              "TauA":"auto",
-              "VirA":"auto",
-              "HydraA":"auto" },
+          "sources": [],
           "time_steps":10,
           "ignore_target":false,
           "frequency_steps":64
@@ -643,13 +631,7 @@
           "autocorrelations":true
         },
         "demix":{
-          "sources":{
-              "CasA":"auto",
-              "CygA":"auto",
-              "HerA":"auto",
-              "TauA":"auto",
-              "VirA":"auto",
-              "HydraA":"auto" },
+          "sources": [],
           "time_steps":10,
           "ignore_target":false,
           "frequency_steps":64
@@ -674,13 +656,7 @@
           "autocorrelations":true
         },
         "demix":{
-          "sources":{
-              "CasA":"auto",
-              "CygA":"auto",
-              "HerA":"auto",
-              "TauA":"auto",
-              "VirA":"auto",
-              "HydraA":"auto" },
+          "sources": [],
           "time_steps":10,
           "ignore_target":false,
           "frequency_steps":64
diff --git a/SAS/TMSS/backend/src/tmss/tmssapp/schemas/UC1-scheduling-unit-observation-strategy.json b/SAS/TMSS/backend/src/tmss/tmssapp/schemas/UC1-scheduling-unit-observation-strategy.json
index e7655c9202c304138cbeec89f80f85216257a20e..b2fa516e2b915a27f25d9dc05cb4abaff7c16b47 100644
--- a/SAS/TMSS/backend/src/tmss/tmssapp/schemas/UC1-scheduling-unit-observation-strategy.json
+++ b/SAS/TMSS/backend/src/tmss/tmssapp/schemas/UC1-scheduling-unit-observation-strategy.json
@@ -25,13 +25,7 @@
           "autocorrelations": true
         },
         "demix": {
-          "sources":{
-              "CasA":"auto",
-              "CygA":"auto",
-              "HerA":"auto",
-              "TauA":"auto",
-              "VirA":"auto",
-              "HydraA":"auto" },
+          "sources": [],
           "time_steps": 10,
           "ignore_target": false,
           "frequency_steps": 64
@@ -120,13 +114,7 @@
           "autocorrelations": true
         },
         "demix": {
-          "sources":{
-              "CasA":"auto",
-              "CygA":"auto",
-              "HerA":"auto",
-              "TauA":"auto",
-              "VirA":"auto",
-              "HydraA":"auto" },
+          "sources": [],
           "time_steps": 10,
           "ignore_target": false,
           "frequency_steps": 64
@@ -149,13 +137,7 @@
           "autocorrelations": true
         },
         "demix": {
-          "sources":{
-              "CasA":"auto",
-              "CygA":"auto",
-              "HerA":"auto",
-              "TauA":"auto",
-              "VirA":"auto",
-              "HydraA":"auto" },
+          "sources": [],
           "time_steps": 10,
           "ignore_target": false,
           "frequency_steps": 64
@@ -193,13 +175,7 @@
           "autocorrelations": true
         },
         "demix": {
-          "sources":{
-              "CasA":"auto",
-              "CygA":"auto",
-              "HerA":"auto",
-              "TauA":"auto",
-              "VirA":"auto",
-              "HydraA":"auto" },
+          "sources": [],
           "time_steps": 10,
           "ignore_target": false,
           "frequency_steps": 64
diff --git a/SAS/TMSS/backend/src/tmss/tmssapp/schemas/responsive_telescope_HBA_LoTSS-scheduling_unit_observation-strategy-1.json b/SAS/TMSS/backend/src/tmss/tmssapp/schemas/responsive_telescope_HBA_LoTSS-scheduling_unit_observation-strategy-1.json
index aded1dbe41f84d85b9331afb95d858e5a9e5b805..6384fa54aac12fc9674551cdceb00b93ee7fe6a6 100644
--- a/SAS/TMSS/backend/src/tmss/tmssapp/schemas/responsive_telescope_HBA_LoTSS-scheduling_unit_observation-strategy-1.json
+++ b/SAS/TMSS/backend/src/tmss/tmssapp/schemas/responsive_telescope_HBA_LoTSS-scheduling_unit_observation-strategy-1.json
@@ -16,13 +16,7 @@
           "autocorrelations": true
         },
         "demix": {
-          "sources":{
-              "CasA":"auto",
-              "CygA":"auto",
-              "HerA":"auto",
-              "TauA":"auto",
-              "VirA":"auto",
-              "HydraA":"auto" },
+          "sources": [],
           "time_steps": 10,
           "ignore_target": false,
           "frequency_steps": 64
@@ -379,13 +373,7 @@
           "autocorrelations": true
         },
         "demix": {
-          "sources":{
-              "CasA":"auto",
-              "CygA":"auto",
-              "HerA":"auto",
-              "TauA":"auto",
-              "VirA":"auto",
-              "HydraA":"auto" },
+          "sources": [],
           "time_steps": 10,
           "ignore_target": false,
           "frequency_steps": 64
@@ -562,4 +550,4 @@
     }
   },
   "scheduling_constraints_template": "constraints"
-}
\ No newline at end of file
+}
diff --git a/SAS/TMSS/backend/src/tmss/tmssapp/schemas/short-observation-pipeline-ingest-scheduling-unit-observation-strategy.json b/SAS/TMSS/backend/src/tmss/tmssapp/schemas/short-observation-pipeline-ingest-scheduling-unit-observation-strategy.json
index d6a5fabba170d6592c2a40f89c182a152300e5da..09942c4310d010053b3159a80f5f88ecbac69e7e 100644
--- a/SAS/TMSS/backend/src/tmss/tmssapp/schemas/short-observation-pipeline-ingest-scheduling-unit-observation-strategy.json
+++ b/SAS/TMSS/backend/src/tmss/tmssapp/schemas/short-observation-pipeline-ingest-scheduling-unit-observation-strategy.json
@@ -58,13 +58,7 @@
           "autocorrelations": true
         },
         "demix": {
-          "sources":{
-              "CasA":"auto",
-              "CygA":"auto",
-              "HerA":"auto",
-              "TauA":"auto",
-              "VirA":"auto",
-              "HydraA":"auto" },
+          "sources": [],
           "time_steps": 10,
           "ignore_target": false,
           "frequency_steps": 64
diff --git a/SAS/TMSS/backend/src/tmss/tmssapp/schemas/task_template-preprocessing_pipeline-1.json b/SAS/TMSS/backend/src/tmss/tmssapp/schemas/task_template-preprocessing_pipeline-1.json
index 430818d9644a75160ed78498160aa3cbd44f4cba..81b6a537a92c6d485d3b8024e2655533c74b4221 100644
--- a/SAS/TMSS/backend/src/tmss/tmssapp/schemas/task_template-preprocessing_pipeline-1.json
+++ b/SAS/TMSS/backend/src/tmss/tmssapp/schemas/task_template-preprocessing_pipeline-1.json
@@ -70,51 +70,23 @@
       "required": [],
       "properties": {
         "sources": {
-          "type": "object",
-          "title": "Sources",
-          "default": {
-            "CasA": "no",
-            "CygA": "no",
-            "HerA": "no",
-            "TauA": "no",
-            "VirA": "no",
-            "HydraA": "no"
-          },
-          "required": [
-            "CasA",
-            "CygA",
-            "HerA",
-            "HydraA",
-            "TauA",
-            "VirA"
-          ],
-          "properties": {
-            "CasA": {
-              "$ref": "http://scu199.control.lofar:8008/api/schemas/commonschematemplate/pipeline/1#/definitions/demix_strategy",
-              "title": "CasA"
-            },
-            "CygA": {
-              "$ref": "http://scu199.control.lofar:8008/api/schemas/commonschematemplate/pipeline/1#/definitions/demix_strategy",
-              "title": "CygA"
-            },
-            "HerA": {
-              "$ref": "http://scu199.control.lofar:8008/api/schemas/commonschematemplate/pipeline/1#/definitions/demix_strategy",
-              "title": "HerA"
-            },
-            "TauA": {
-              "$ref": "http://scu199.control.lofar:8008/api/schemas/commonschematemplate/pipeline/1#/definitions/demix_strategy",
-              "title": "TauA"
-            },
-            "VirA": {
-              "$ref": "http://scu199.control.lofar:8008/api/schemas/commonschematemplate/pipeline/1#/definitions/demix_strategy",
-              "title": "VirA"
-            },
-            "HydraA": {
-              "$ref": "http://scu199.control.lofar:8008/api/schemas/commonschematemplate/pipeline/1#/definitions/demix_strategy",
-              "title": "HyrdraA"
-            }
-          },
-          "additionalProperties": false
+          "type": "array",
+          "minItems": 0,
+          "maxItems": 2,
+          "uniqueItems": true,
+          "additionalItems": false,
+          "items": {
+            "type": "string",
+            "default": "CasA",
+            "enum": [
+              "CasA",
+              "CygA",
+              "HerA",
+              "HydraA",
+              "TauA",
+              "VirA"
+            ]
+          }
         },
         "time_steps": {
           "type": "integer",
diff --git a/SAS/TMSS/backend/src/tmss/tmssapp/subtasks.py b/SAS/TMSS/backend/src/tmss/tmssapp/subtasks.py
index ce2d4c74b035198d660acfa6293cf772a453a9fa..9e79c6d55e3537e7f3257051b88f330df8095123 100644
--- a/SAS/TMSS/backend/src/tmss/tmssapp/subtasks.py
+++ b/SAS/TMSS/backend/src/tmss/tmssapp/subtasks.py
@@ -2095,8 +2095,8 @@ def _generate_subtask_specs_from_preprocessing_task_specs(preprocessing_task_spe
     subtask_specs['demixer']["demix_frequency_steps"] = preprocessing_task_specs['demix']['frequency_steps']
     subtask_specs['demixer']["demix_time_steps"]      = preprocessing_task_specs['demix']['time_steps']
     subtask_specs['demixer']["ignore_target"]         = preprocessing_task_specs['demix']['ignore_target']
-    subtask_specs['demixer']["demix_always"]          = [source for source,strategy in preprocessing_task_specs['demix']['sources'].items() if strategy == "yes"]
-    subtask_specs['demixer']["demix_if_needed"]       = [source for source,strategy in preprocessing_task_specs['demix']['sources'].items() if strategy == "auto"]
+    subtask_specs['demixer']["demix_always"]          = preprocessing_task_specs['demix']['sources']
+    subtask_specs['demixer']["demix_if_needed"]       = []
 
     # flagging
     if preprocessing_task_specs["flag"]["rfi_strategy"] != 'none':