[R-sig-ME] Failure to converge with glmer on gamma data

[moses selebatso]

Hello
I m trying to determine the effects of season and habitat on forage protein content. With my replica nested within location. 
model<-glmer(Protein~Habitat*Season + (1|Location/Replica), family=Gamma)
I am getting a warning when running my model. I have tried read on previous post and most of the time I get lost because I fairly new to R. I understand there is a maximum "maxlgradl" of 0.001 that should be accepted in this kind of warnings. However, mine is a little higher than that. Can someone advise how I can proceed here and get an acceptable output.
I also tried using "....family =Gamma(log)"  instead of just "....family = Gamma" and it doesn't give me the warning. Can this be an acceptable option? 
Model and output below. I can provide data sample if needed.
> model<-glmer(Protein~Habitat*Season + (1|Location/Replica), family=Gamma)
Warning message:
In checkConv(attr(opt, "derivs"), opt$par, ctrl = control$checkConv,  :
  Model failed to converge with max|grad| = 0.00123611 (tol = 0.001, component 1)
> model2<-glmer(Protein~Habitat+Season + (1|Location/Replica), family=Gamma)
Warning message:
In checkConv(attr(opt, "derivs"), opt$par, ctrl = control$checkConv,  :
  Model failed to converge with max|grad| = 0.00254076 (tol = 0.001, component 1)


 Thank you

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