diff --git a/app/components/DurationInput.tsx b/app/components/DurationInput.tsx
index 45c514c..83db646 100644
--- a/app/components/DurationInput.tsx
+++ b/app/components/DurationInput.tsx
@@ -1,7 +1,7 @@
 import * as React from "react";
 import { Input, InputProps } from "semantic-ui-react";
 
-import { Duration } from "@common/sprinklers";
+import { Duration } from "@common/Duration";
 
 export default class DurationInput extends React.Component<{
     duration: Duration,
diff --git a/app/components/ProgramTable.tsx b/app/components/ProgramTable.tsx
index 8571bb7..0e290e5 100644
--- a/app/components/ProgramTable.tsx
+++ b/app/components/ProgramTable.tsx
@@ -2,6 +2,7 @@ import { observer } from "mobx-react";
 import * as React from "react";
 import { Table } from "semantic-ui-react";
 
+import { Duration } from "@common/Duration";
 import { Program, Schedule } from "@common/sprinklers";
 
 @observer
@@ -20,10 +21,12 @@ export default class ProgramTable extends React.Component<{ programs: Program[]
             return null;
         }
         const { name, running, enabled, schedule, sequence } = program;
-        const sequenceItems = sequence.map((item, index) => (
-            <li key={index}>Section {item.section + 1 + ""} for&nbsp;
-                {item.duration.minutes}M {item.duration.seconds}S</li>
-        ));
+        const sequenceItems = sequence.map((item, index) => {
+            const duration = Duration.fromSeconds(item.duration);
+            return (
+                <li key={index}>Section {item.section + 1 + ""} for {duration.toString()}</li>
+            );
+        });
         return [(
             <Table.Row key={i}>
                 <Table.Cell className="program--number">{"" + (i + 1)}</Table.Cell>
diff --git a/app/components/RunSectionForm.tsx b/app/components/RunSectionForm.tsx
index 9db0e48..a4de427 100644
--- a/app/components/RunSectionForm.tsx
+++ b/app/components/RunSectionForm.tsx
@@ -3,8 +3,9 @@ import { observer } from "mobx-react";
 import * as React from "react";
 import { DropdownItemProps, DropdownProps, Form, Header, Segment } from "semantic-ui-react";
 
+import { Duration } from "@common/Duration";
 import log from "@common/logger";
-import { Duration, Section } from "@common/sprinklers";
+import { Section } from "@common/sprinklers";
 import DurationInput from "./DurationInput";
 
 @observer
@@ -17,7 +18,7 @@ export default class RunSectionForm extends React.Component<{
     constructor() {
         super();
         this.state = {
-            duration: new Duration(1, 1),
+            duration: new Duration(0, 0),
             section: "",
         };
     }
@@ -67,7 +68,7 @@ export default class RunSectionForm extends React.Component<{
         }
         const section: Section = this.props.sections[this.state.section];
         const { duration } = this.state;
-        section.run(duration)
+        section.run(duration.toSeconds())
             .then((result) => log.debug({ result }, "requested section run"))
             .catch((err) => log.error(err, "error running section"));
     }
diff --git a/common/sprinklers/Duration.ts b/common/Duration.ts
similarity index 100%
rename from common/sprinklers/Duration.ts
rename to common/Duration.ts
diff --git a/common/sprinklers/Program.ts b/common/sprinklers/Program.ts
index 8675d54..a832ece 100644
--- a/common/sprinklers/Program.ts
+++ b/common/sprinklers/Program.ts
@@ -1,15 +1,14 @@
 import { observable } from "mobx";
-import { Duration } from "./Duration";
 import { Schedule } from "./schedule";
 import { SprinklersDevice } from "./SprinklersDevice";
 
 export class ProgramItem {
     // the section number
     readonly section: number;
-    // duration of the run
-    readonly duration: Duration;
+    // duration of the run, in seconds
+    readonly duration: number;
 
-    constructor(section: number = 0, duration: Duration = new Duration()) {
+    constructor(section: number = 0, duration: number = 0) {
         this.section = section;
         this.duration = duration;
     }
diff --git a/common/sprinklers/Section.ts b/common/sprinklers/Section.ts
index 2d6df89..3f8c710 100644
--- a/common/sprinklers/Section.ts
+++ b/common/sprinklers/Section.ts
@@ -1,5 +1,4 @@
 import { observable } from "mobx";
-import { Duration } from "./Duration";
 import { SprinklersDevice } from "./SprinklersDevice";
 
 export class Section {
@@ -14,7 +13,8 @@ export class Section {
         this.id = id;
     }
 
-    run(duration: Duration) {
+    /** duration is in seconds */
+    run(duration: number) {
         return this.device.runSection({ sectionId: this.id, duration });
     }
 
diff --git a/common/sprinklers/SectionRunner.ts b/common/sprinklers/SectionRunner.ts
index f6fa969..e4d2d56 100644
--- a/common/sprinklers/SectionRunner.ts
+++ b/common/sprinklers/SectionRunner.ts
@@ -1,12 +1,11 @@
 import { observable } from "mobx";
-import { Duration } from "./Duration";
 import { SprinklersDevice } from "./SprinklersDevice";
 
 export class SectionRun {
     readonly sectionRunner: SectionRunner;
     readonly id: number;
     section: number;
-    duration: Duration = new Duration();
+    duration: number = 0;
     startTime: Date | null = null;
     pauseTime: Date | null = null;
 
diff --git a/common/sprinklers/index.ts b/common/sprinklers/index.ts
index 8aad53d..b6d7175 100644
--- a/common/sprinklers/index.ts
+++ b/common/sprinklers/index.ts
@@ -1,4 +1,4 @@
-export * from "./Duration";
+// export * from "./Duration";
 export * from "./ISprinklersApi";
 export * from "./Program";
 export * from "./schedule";
diff --git a/common/sprinklers/requests.ts b/common/sprinklers/requests.ts
index f7c5c10..c688e45 100644
--- a/common/sprinklers/requests.ts
+++ b/common/sprinklers/requests.ts
@@ -1,5 +1,3 @@
-import { Duration } from "./Duration";
-
 export interface WithType<Type extends string = string> {
     type: Type;
 }
@@ -15,7 +13,7 @@ export type UpdateProgramResponse = Response<"updateProgram", { data: any }>;
 
 export interface WithSection { sectionId: number; }
 
-export type RunSectionData = WithSection & { duration: Duration };
+export type RunSectionData = WithSection & { duration: number };
 export type RunSectionReqeust = RunSectionData & WithType<"runSection">;
 export type RunSectionResponse = Response<"runSection", { runId: number }>;
 
diff --git a/common/sprinklers/schema/common.ts b/common/sprinklers/schema/common.ts
index 04624c2..82ca2cb 100644
--- a/common/sprinklers/schema/common.ts
+++ b/common/sprinklers/schema/common.ts
@@ -3,17 +3,7 @@ import {
 } from "serializr";
 import * as s from "..";
 
-export const duration: PropSchema = {
-    serializer: (d: s.Duration | null) =>
-        d != null ? d.toSeconds() : null,
-    deserializer: (json: any, done) => {
-        if (typeof json === "number") {
-            done(null, s.Duration.fromSeconds(json));
-        } else {
-            done(new Error(`Duration expects a number, not ${json}`), undefined);
-        }
-    },
-};
+export const duration: PropSchema = primitive();
 
 export const date: PropSchema = {
     serializer: (jsDate: Date | null) => jsDate != null ?