Are you using a digital probe thermometer in your tank? If not I would get one the stick on digital is only giving you ambient temps-- as long as shes not eating the substrate and your not noticing any of it in the poop your good - let us know how that jungle bar does -Hi.
Yes I have just bought it from my local shop.
PS- I know some will say remove substrate, however as long as the conditions and diet is good then substrate is ok to use. She doesn't eat it or anything and this substrate isn't dusty and it's recommended but I respect others opinions.