Yes, it is fine. I have the same skimmer and have been using it for about 4 years now, and that’s how I’ve always had it set up. As long as you have good circulation in your tank, it will be fine. If you are worried about the two heads being too close to each other, you can point them out to the left and to the right at angles to put more space between them, like this / \. Other than that, you shouldn’t have any problems. This skimmer has always done well for me. Just be careful with the ceramic rod/axle in the motor when you clean it. I have broken 3 of them, and it is like $25 to replace it.