diff --git a/PROFANITY_RULES.yml b/PROFANITY_RULES.yml
new file mode 100644
index 0000000..1e6c803
--- /dev/null
+++ b/PROFANITY_RULES.yml
@@ -0,0 +1,4 @@
+go-sdk:
+  excludeFiles: [ "*_test.go" ]
+  importsContain: [ github.com/blend/go-sdk/* ]
+  description: "please don't use go-sdk in this repo"
\ No newline at end of file
diff --git a/times.go b/times.go
index 1a21f48..95e2acd 100644
--- a/times.go
+++ b/times.go
@@ -3,8 +3,6 @@ package chart
 import (
 	"sort"
 	"time"
-
-	"github.com/blend/go-sdk/timeutil"
 )
 
 // Assert types implement interfaces.
@@ -29,7 +27,7 @@ func (t Times) Len() int {
 
 // GetValue returns a value at an index as a time.
 func (t Times) GetValue(index int) float64 {
-	return timeutil.ToFloat64(t[index])
+	return ToFloat64(t[index])
 }
 
 // Swap implements sort.Interface.
@@ -41,3 +39,8 @@ func (t Times) Swap(i, j int) {
 func (t Times) Less(i, j int) bool {
 	return t[i].Before(t[j])
 }
+
+// ToFloat64 returns a float64 representation of a time.
+func ToFloat64(t time.Time) float64 {
+	return float64(t.UnixNano())
+}