diff --git a/models/staging/xedotcom/schema.yml b/models/staging/xedotcom/schema.yml
index 5d1fa96..33785cd 100644
--- a/models/staging/xedotcom/schema.yml
+++ b/models/staging/xedotcom/schema.yml
@@ -5,7 +5,7 @@ models:
       record holds a currency pair for a specific day. 
 
       Reverse rates are explicit. This means that, for any given day and any
-      given currency pair. you will find two records with opposite from/to
+      given currency pair, you will find two records with opposite from/to
       positions. So, for 2024-01-01, you will find both a EUR->USD record and a
       USD->EUR record with the opposite rate (1/rate).
     columns:
@@ -28,8 +28,8 @@ models:
           - not_null
       - name: rate
         description: >-
-          The exchange rate, represnted as the units of the target currency that
-          one unit of source currency gets you. So, from_currency=USD to
+          The exchange rate, represented as the units of the target currency
+          that one unit of source currency gets you. So, from_currency=USD to
           to_currency=PLN with rate=4.2 should be read as '1 US Dollar buys me
           4.2 Polish Zlotys'.
 
@@ -39,6 +39,7 @@ models:
           The rate can be smaller than one, but can't be negative.
         data_type: numeric
         tests:
+          - not_negative_or_zero
           - not_null
       - name: rate_date_utc
         description: The date in which the rate record is relevant.