@Michael J. Most of this is market dependent. I can tell you what is working for us in the Midwest but it may not necessarily work where you are. So take this for what it is worth. Our minimum requirements are:
-Gross monthly income 3x the rent
-Credit score of 550
-No violent felonies ever or non-violent felonies in the past 7 years
-No evictions in past 7 years
Our security deposit is equal to one month’s rent. Sometimes we will reduce the deposit for a special when units are harder to lease.
I recommend trying to get feedback if possible to know why they are choosing not to apply. If you have strong minimum requirements, the likelihood of them damaging the property and you needing such a large deposit is lower. In our market you don’t see deposits over 1 months rent, but if that is common in your market then that may not be the issue. We collect the security deposit at lease signing, and the first month's rent at the time of move in. One of our biggest issues is that people don't have a lot of savings, so moving in is expensive and them being able to pay the deposit now and the rent in two weeks when they move in and get another paycheck helps out with that. Is there a reason your rent is $100 below the median? That's fine if that is the market rate for your property. I just want to make sure you're not renting it $100 below what you should be able to get for the property.
I would hold firm on your income requirement, and I’d say the credit requirement is market/property specific too. Good luck!