diff --git a/R/predConc.R b/R/predConc.R
index 7f79fda..386167e 100644
--- a/R/predConc.R
+++ b/R/predConc.R
@@ -43,13 +43,17 @@
 #' @export
 predConc <- function(fit, newdata, by="day", 
                      allow.incomplete=FALSE, conf.int=0.95) {
-  ##
+  
   ## By options and other preliminary code
-  if(is.null(fit$cfit))
+  if(is.null(fit$cfit)) {
     stop("model cannot predict concentration values")
-  if(nrow(newdata) > 176000L)
+  }
+    
+  if(nrow(newdata) > 176000L) {
     stop("newdata has too many rows, the size limit is 176000")
+  }
   ByOpt <- c("unit", "day")
+  match.arg('by', ByOpt)
   Qadj <- fit$Qadj
   Tadj <- fit$Tadj
   flow <- fit$flow
diff --git a/R/predLoad.R b/R/predLoad.R
index 5512db1..d7b4090 100644
--- a/R/predLoad.R
+++ b/R/predLoad.R
@@ -64,9 +64,11 @@ predLoad <- function(fit, newdata, load.units=fit$load.units, by="total",
   ##    2014Sep23 DLLorenz Missing check on newdata
   ##
   ## By options and other preliminary code
-  if(nrow(newdata) > 176000L)
+  if(nrow(newdata) > 176000L) {
     stop("newdata has too many rows, the size limit is 176000")
+  }
   ByOpt <- c("unit", "day", "month", "water year", "calendar year", "total")
+  match.arg(by, ByOpt)
   load.units
   seopt <- match.arg(seopt, c("exact", "approximate"))
   Qadj <- fit$Qadj