What do you mean when you say, "up and assumed room temperature." ?
A 30 gallon tank is considered a minimum for most sand-sifting gobies. Its better for the tank to be established where the sand will be live and have adequate populations of zooplankton. Usually, however, it is almost a must that the goby eats prepared foods, frozen or dried. A larger tank is usually better though because the sand has a better chance of being able to support a sand-sifter. I have kept many sand-sifters and I can say it is much better if you know they will eat prepared foods before you purchase them. Also I have found it is really a necessity that the sand grain size is the right size. I believe it should be small, but not too small. 1.0mm-2.0mm, I believe. If your sand is under 1.0mm its oolitic sand and can still be sifted by the gobies, but it is not considered the appropriate size for a few reasons, one of which is that the goby will have a hard time burrowing their holes as they easily collapse. Other reasons are probably that there's more plankton life in larger grain sizes. There's probably more reasons against oolitic sand that I am forgeting. Larger sand grains over 2.0mm, or around this, is too large as they can not sift it through their gills or it may cause harm to them if they try. So for keeping sand-sifter gobies it really is imperative that the sand is of the correct size for they can very well starve if it isn't. And please read some info on this because I probably missed a few points.