diff --git a/pkg/tsdb/testdatasource/sims/engine.go b/pkg/tsdb/testdatasource/sims/engine.go
index f2e0ba33500..fa18df54bc6 100644
--- a/pkg/tsdb/testdatasource/sims/engine.go
+++ b/pkg/tsdb/testdatasource/sims/engine.go
@@ -66,6 +66,7 @@ func NewSimulationEngine() (*SimulationEngine, error) {
 	initializers := []simulationInitializer{
 		newFlightSimInfo,
 		newSinewaveInfo,
+		newTankSimInfo,
 	}
 
 	for _, init := range initializers {
@@ -155,7 +156,10 @@ func (s *SimulationEngine) QueryData(ctx context.Context, req *backend.QueryData
 			maxPoints := q.MaxDataPoints * 2
 			for i := int64(0); i < maxPoints && timeWalkerMs < to; i++ {
 				t := time.UnixMilli(timeWalkerMs).UTC()
-				appendFrameRow(frame, sim.GetValues(t))
+				vals := sim.GetValues(t)
+				if vals != nil { // nil is returned when you ask for an invalid time
+					appendFrameRow(frame, vals)
+				}
 				timeWalkerMs += stepMillis
 			}
 		}
diff --git a/pkg/tsdb/testdatasource/sims/tank.go b/pkg/tsdb/testdatasource/sims/tank.go
new file mode 100644
index 00000000000..ce8c1626374
--- /dev/null
+++ b/pkg/tsdb/testdatasource/sims/tank.go
@@ -0,0 +1,152 @@
+package sims
+
+import (
+	"time"
+
+	"github.com/grafana/grafana-plugin-sdk-go/data"
+)
+
+type tankSim struct {
+	key   simulationKey
+	cfg   tankConfig
+	state tankState
+}
+
+var (
+	_ Simulation = (*tankSim)(nil)
+)
+
+type tankConfig struct {
+	TankCapacity float64 `json:"tankCapacity"` // size (in gallons) of the tank
+	FillRate     float64 `json:"fillRate"`     // fillRate
+	DrainRate    float64 `json:"drainRate"`    // how fast it will drain (when valve is open)
+	DrainOpen    bool    `json:"drainOpen"`
+	PumpOn       bool    `json:"pumpOn"`
+}
+
+type tankState struct {
+	Time        time.Time
+	FillPercent float64 // 0-1
+}
+
+func (s *tankSim) GetState() simulationState {
+	return simulationState{
+		Key:    s.key,
+		Config: s.cfg,
+	}
+}
+
+func (s *tankSim) SetConfig(vals map[string]interface{}) error {
+	return updateConfigObjectFromJSON(&s.cfg, vals)
+}
+
+func (s *tankSim) NewFrame(size int) *data.Frame {
+	frame := data.NewFrameOfFieldTypes("", size,
+		data.FieldTypeTime,    // time
+		data.FieldTypeFloat64, // value
+		data.FieldTypeFloat64, // value
+		data.FieldTypeBool,
+		data.FieldTypeBool,
+	)
+
+	var min data.ConfFloat64 = 0.0
+	var max data.ConfFloat64 = 1.0
+
+	frame.Fields[0].Name = "time"
+	frame.Fields[1].Name = "percentFull"
+	frame.Fields[1].Config = &data.FieldConfig{
+		Unit: "percentunit",
+		Min:  &min,
+		Max:  &max,
+	}
+
+	frame.Fields[2].Name = "tankVolume"
+	frame.Fields[2].Config = &data.FieldConfig{
+		Unit: "m3", // cubic meters
+	}
+	frame.Fields[3].Name = "pumpOn"
+	frame.Fields[4].Name = "drainOpen"
+	return frame
+}
+
+func (s *tankSim) GetValues(t time.Time) map[string]interface{} {
+	if t.Before(s.state.Time) {
+		return nil // can not look backwards!
+	}
+	if t.After(s.state.Time) {
+		elapsed := t.Sub(s.state.Time).Seconds()
+		v := s.state.FillPercent * s.cfg.TankCapacity
+		if s.cfg.PumpOn {
+			v += (elapsed * s.cfg.FillRate)
+		}
+		if s.cfg.DrainOpen {
+			v -= (elapsed * s.cfg.DrainRate)
+		}
+
+		p := v / s.cfg.TankCapacity
+		if p > 1 {
+			p = 1
+		} else if p < 0 {
+			p = 0
+		}
+
+		s.state.FillPercent = p
+		s.state.Time = t
+	}
+
+	return map[string]interface{}{
+		"time":        s.state.Time,
+		"percentFull": s.state.FillPercent,
+		"tankVolume":  s.state.FillPercent * s.cfg.TankCapacity,
+		"pumpOn":      s.cfg.PumpOn,
+		"drainOpen":   s.cfg.DrainOpen,
+	}
+}
+
+func (s *tankSim) Close() error {
+	return nil
+}
+
+func newTankSimInfo() simulationInfo {
+	tc := tankConfig{
+		TankCapacity: 100.0,
+		FillRate:     1.0, // gallons/min?
+		DrainRate:    0.5, // `json:"drainRate,omitempty"` // how fast it will drain (when valve is open)
+		DrainOpen:    false,
+		PumpOn:       true,
+	}
+	ts := tankState{
+		Time:        time.Now(),
+		FillPercent: .6,
+	}
+
+	df := data.NewFrame("")
+	df.Fields = append(df.Fields, data.NewField("tankCapacity", nil, []float64{tc.TankCapacity}).SetConfig(&data.FieldConfig{
+		Unit: "m3",
+	}))
+	df.Fields = append(df.Fields, data.NewField("fillRate", nil, []float64{tc.FillRate}).SetConfig(&data.FieldConfig{
+		Unit: "cms",
+	}))
+	df.Fields = append(df.Fields, data.NewField("drainRate", nil, []float64{tc.DrainRate}).SetConfig(&data.FieldConfig{
+		Unit: "cms",
+	}))
+	df.Fields = append(df.Fields, data.NewField("drainOpen", nil, []bool{tc.DrainOpen}))
+	df.Fields = append(df.Fields, data.NewField("pumpOn", nil, []bool{tc.PumpOn}))
+
+	return simulationInfo{
+		Type:        "tank",
+		Name:        "Tank",
+		Description: "Fill and drain a water tank",
+		SetupFields: df,
+		OnlyForward: false,
+		create: func(cfg simulationState) (Simulation, error) {
+			s := &tankSim{
+				key:   cfg.Key,
+				cfg:   tc,
+				state: ts,
+			}
+			err := updateConfigObjectFromJSON(&s.cfg, cfg.Config) // override any fields
+			return s, err
+		},
+	}
+}
diff --git a/public/app/plugins/datasource/testdata/components/SimulationQueryEditor.tsx b/public/app/plugins/datasource/testdata/components/SimulationQueryEditor.tsx
index 3b566970220..6016af7b874 100644
--- a/public/app/plugins/datasource/testdata/components/SimulationQueryEditor.tsx
+++ b/public/app/plugins/datasource/testdata/components/SimulationQueryEditor.tsx
@@ -10,6 +10,7 @@ export const SimulationQueryEditor = ({ onChange, query }: EditorProps) => {
   const options = [
     { label: 'Flight', value: 'flight' },
     { label: 'Sine', value: 'sine' },
+    { label: 'Tank', value: 'tank' },
   ];
 
   const onUpdateKey = (key: typeof simQuery.key) => {