I understood that you were watering and then spraying...
Well, if you are only spraying, then you maybe are underwatering, but if you water it and then spray it, you're maybe overwatering, well, the idea behind watering, is to give the tree the water when it needs it, not with a schedule...
As an example, here in Guatemala we're in such a thing called "canícula" that is a time in the middle of the rainy season, when you can have full sun and the next day a stormy rain, so what I do, is something that you can do to know when to water, and when don't water...
I learned this trick here, and had posted it for a few times, but I will keep doing this because I find it really important... The trick is to stick a chopstick or a skewer stick in the soil, then use it as a meter, before watering take out the stick and check the soil moist, if the stick is wet, don't water, and if it's dry, oopss... you've gone to far, water it quickly...
The idea is to water when the stick is starting to dry, I don't know well elms (I don't have one indeed), but you can check for the species info, because if it needs lots of water you must give it to the tree, if it needs to dryout before getting more water, you must let it dryout. So, the species specific you can check them in
Bonsai BCI
Good luck with your tree...