My employer used my PTO without me telling them to. How do I gently talk to them about it?

Set up a time to meet with your supervisor and do not be gentle about this or do this by email. They are taking advantage of you and they do not think you have the confidence to complain openly. You need to tell them to their face about all the additional hours you work and that they should not be using your paid time off to make up for certain hours when work is slow and if they try to wheedle their way out of it, talk to an attorney.

You should be polite and firm.  Ask for a meeting with your manager, a rep from payroll and a someone from HR.  Say that much to your surprise, there was an error in your last paycheck that applied some PTO that you didn't take.

In most companies, the employee must fill out a form requesting PTO.  If you didn't fill one out, then the company committed either an error or fraud.  It is that simple.  They need to give you your time back.  It is possible that this company has a policy where they will force employees to take PTO or buy you out, but you still have to make the request.  

Hold them at gunpoint and tell 'em to give it back or else.

If you worked less than 40 hours...they may have been right to do this...

Since you are salary, they arent paying you by the hour...

Tricky situation...I dont think they are right here, but would need to know more about your contract and/or job description.  

An exempt employee is usually the same as a salaried employee.

An exempt employee gets paid for the work they do not the time it takes them to do the job.

A non-exempt employee is usually the same as an hourly employee.  They get paid for the time it takes to do the work.

There is a third designation called salaried non-exempt.  It doesn't sound like you are one of these.In the USA, if you are an exempt employee, if you work (real work) at any time during the day, you get paid for the full day.  In some states, like California, many employers interpret the law to be if you work any time in the week, you get paid for the full week.

That said, it's legal to supplement any time not worked with accrued PTO.

If you run out of PTO, if you don't work on a day (or week in selected states), you don't get paid for that day.  If your 34 hours last week were over 4 days, then it was handled the way most companies would have.On the flip side, if the standard hours for the week are 45-55 (included in your job description) and it's not uncommon to work many more, you would generally be paid a higher than someone who generally works 40 or less.  This might be part of your bonus or your regular pay.

-- If it's not, why did you take the job?

Instead of complaining about them using your PTO.  Ask them how you are supposed to take time off during the busy season when you need it / can't avoid it, if all your time is used during the slow period. 

just bring it up in a nice way. Make sure you are keeping up with your hours on your own too.

Maybe have them consult you before using the PTO?

It's also not legal unless you fall under the rules as an exempt employee. The rules are a bit complex so it will take some study to figure out which rule(s) you fall under. Here is the place to start: https://www.dol.gov/ › whd › overtime

Unfortunately there's no real legal protection for PTO time for salary employees since it's considered merely a voluntary benefit given by the employer.   What they are doing is extremely crappy, but is perfectly legal as long as they never dock your pay for those shorter weeks if your PTO runs out.   You need to air your grievances with your manager, but much like asking for a raise if they refuse you don't have much recourse other than finding another job.  A way around it would be to use your PTO before they can get a chance to take it, but it's a stupid game.  Hopefully they will see you as a valuable employee and do the right thing.  

You can say whatever it is you wish, they do not care. They knew they would be doing this and they know. You signed the contract.

I completely agree with your point of view. 

However, unless your contract or employee handbook states that you receive compensatory time off in lieu of pay for hours above and beyond the 55, you're probably out of luck.

If your contract states that you should work 55 hours per week, I suggest you start doing that unless your employer is willing to put the comp-time policy in writing. 

But yes, if you're a full-time employee and you take time off, that's what PTO is for, especially if there is not a comp-time policy in place.

Are your hours worked documented in any formal way?   Time clock or time sheet?   In order to be approved for compensatory time off, you may have to prove how much comp time you've accrued. 

Any reasonable employer will understand your point of view and work towards finding a solution.  Yours may or may not be reasonable.

Good luck!