increasing running time

How long has it been since you last increased your time? It's recommended not to increase your mileage by more than 10% per week, and to run at that new mileage for at least 3 weeks before increasing again. 6 miles per hour for 30 minutes is 3 miles, so if you're running 3 days a week, your weekly mileage is 9. Your proposed new weekly mileage is 10.5. That is a little bit more than 10%, but it sounds pretty reasonable. If you've been running 9 miles a week for a few weeks and everything seems good, there's no reason not to try it.

Wow, that was hard to follow :laugh:.
I run 6-7 days a week
at a 6-7mph
for 30 minutes
I increased my running time I think 3-4 days ago from 25-30.

Why do you run so many days a week? You may find you can run better if you take days off (I personally never run two days in a row for fear of injury). You can probably increase .5-1 mile per week.

Add 0.5-1.0 miles to your daily runs, or I guess 5-10 min. I'd say 0.5 until you are up to 3-4mi. Up it every 3 weeks or so. Bottom line is to err on the side of conservative gains when it comes to running. And try speaking in pace, i.e., 10:00mi/min because math is hard

I think most of the caution in adding miles is because your bones and joints need time to adapt to the stress of impact. Running on an elliptical machine isn't so high-impact. It's all a matter of your cardiovascular fitness. I'd say you should feel free to add as many miles as frequently as you like.