diff --git a/app/src/main/java/net/pokeranalytics/android/calculus/optimalduration/OptimalDurationCalculator.kt b/app/src/main/java/net/pokeranalytics/android/calculus/optimalduration/OptimalDurationCalculator.kt
new file mode 100644
index 00000000..4a5f611a
--- /dev/null
+++ b/app/src/main/java/net/pokeranalytics/android/calculus/optimalduration/OptimalDurationCalculator.kt
@@ -0,0 +1,2 @@
+package net.pokeranalytics.android.calculus.optimalduration
+
diff --git a/app/src/main/java/net/pokeranalytics/android/model/filter/Query.kt b/app/src/main/java/net/pokeranalytics/android/model/filter/Query.kt
index 57569c43..d56f03a4 100644
--- a/app/src/main/java/net/pokeranalytics/android/model/filter/Query.kt
+++ b/app/src/main/java/net/pokeranalytics/android/model/filter/Query.kt
@@ -12,7 +12,7 @@ fun List<Query>.mapFirstCondition() : List<QueryCondition> {
 class Query {
 
 	constructor(vararg elements: QueryCondition) {
-		if (elements.size > 0) {
+		if (elements.isNotEmpty()) {
 			this.add(elements.asList())
 		}
 	}
@@ -23,22 +23,25 @@ class Query {
 			return this._conditions
 		}
 
-	fun add(vararg elements: QueryCondition) {
-		if (elements.size > 0) {
+	fun add(vararg elements: QueryCondition): Query {
+		if (elements.isNotEmpty()) {
 			this.add(elements.asList())
 		}
+		return this
 	}
 
-	fun add(queryCondition: QueryCondition) {
+	fun add(queryCondition: QueryCondition): Query {
 		this._conditions.add(queryCondition)
+		return this
 	}
 
-	fun remove(queryCondition: QueryCondition) {
-		this._conditions.remove(queryCondition)
+	fun add(queryConditions: List<QueryCondition>): Query{
+		this._conditions.addAll(queryConditions)
+		return this
 	}
 
-	fun add(queryConditions: List<QueryCondition>) {
-		this._conditions.addAll(queryConditions)
+	fun remove(queryCondition: QueryCondition) {
+		this._conditions.remove(queryCondition)
 	}
 
     val defaultName: String
@@ -59,28 +62,32 @@ class Query {
 	inline fun <reified T : Filterable> queryWith(query: RealmQuery<T>): RealmQuery<T> {
 		var realmQuery = query
 
-        val queryFromTime = this.conditions.filter {
-            it is QueryCondition.StartedFromTime
-        }.firstOrNull()
-        val queryToTime = this.conditions.filter {
-            it is QueryCondition.EndedToTime
-        }.firstOrNull()
-
-        this.conditions.forEach {
-            if (it is QueryCondition.StartedFromTime) {
-                realmQuery = it.queryWith(realmQuery, queryToTime)
-            } else if (it is QueryCondition.EndedToTime) {
-                realmQuery = it.queryWith(realmQuery, queryFromTime)
-            } else {
-                realmQuery = it.queryWith(realmQuery)
-            }
+        val queryFromTime = this.conditions.firstOrNull {
+	        it is QueryCondition.StartedFromTime
+        }
+		val queryToTime = this.conditions.firstOrNull {
+			it is QueryCondition.EndedToTime
+		}
+
+		this.conditions.forEach {
+			realmQuery = when (it) {
+				is QueryCondition.StartedFromTime -> {
+					it.queryWith(realmQuery, queryToTime)
+				}
+				is QueryCondition.EndedToTime -> {
+					it.queryWith(realmQuery, queryFromTime)
+				}
+				else -> {
+					it.queryWith(realmQuery)
+				}
+			}
 		}
 
 //        println("<<<<<< ${realmQuery.description}")
-        val queryLast = this.conditions.filter {
-            it is QueryCondition.Last
-        }.firstOrNull()
-        queryLast?.let {qc ->
+        val queryLast = this.conditions.firstOrNull {
+	        it is QueryCondition.Last
+        }
+		queryLast?.let {qc ->
             (qc as QueryCondition.Last).singleValue?.let {
                 return realmQuery.limit(it.toLong())
             }
diff --git a/app/src/main/java/net/pokeranalytics/android/model/filter/QueryCondition.kt b/app/src/main/java/net/pokeranalytics/android/model/filter/QueryCondition.kt
index ac94450e..1877363f 100644
--- a/app/src/main/java/net/pokeranalytics/android/model/filter/QueryCondition.kt
+++ b/app/src/main/java/net/pokeranalytics/android/model/filter/QueryCondition.kt
@@ -306,6 +306,9 @@ sealed class QueryCondition : FilterElementRow {
 	abstract class TrueQueryCondition : QueryCondition() {
 		override var operator: Operator = Operator.TRUE
 	}
+	abstract class NotNullQueryCondition : QueryCondition() {
+		override var operator: Operator = Operator.NOTNULL
+	}
 
 	object IsLive : TrueQueryCondition()
 
@@ -601,9 +604,9 @@ sealed class QueryCondition : FilterElementRow {
 		}
 	}
 
-	object DateNotNull : QueryCondition() {
-		override var operator = Operator.NOTNULL
-	}
+	object DateNotNull : NotNullQueryCondition()
+	object EndDateNotNull : NotNullQueryCondition()
+	object BigBlindNotNull : NotNullQueryCondition()
 
 	class StartedFromTime() : TimeQuery() {
 		override var operator = Operator.MORE