You have an installment agreement and you just filed a tax return and you're not going to be able to pay that full balance.

Well if you had asked me I would have told you don't do that but since you have done that it's OK we're going to deal with where you are. What that's going to do is almost certainly negate your current installment agreement. That’s going to put you in a position that they call “out of compliance”. When you are out of compliance that undoes any situation that you've worked out with them and you start all over from scratch. So if you need to, and if your situation justifies it, you're probably going to want to hire a professional to help you re-negotiate another agreement. You will show the IRS how you're going to make a new agreement with them, you're going to keep it and that you're going to take steps in the future to make sure that your current tax liability is included so that the whole does not continue to get bigger. Once you do have an installment agreement in place, one of the requirements of that deal is that you continue to full pay any future tax liability and if you fail to do that it can undo your installment agreement. So definitely think about that while you're working out.