Exhaust fan too strong? sucking in tent sides

[1st timer]

I bought a DR120 and a 5inch exhaust RVK.
It's a bit too strong considering i don't have an intake fan. It's pulling in the sides of the tent slightly, so i feel that it's going to put pressure on the zips and the tent may soon develop small tears.
i don't think an intake fan is really necessary (happy to be corrected). It's going to cost me ££ and it's yet another thing eating away at my electricity bill.

Do you guys have any tips on allowing air to come in easily in a closed up tent?
I can't keep the tent zips open due to light leaks.

much appreciated

[EvilCartman]

I bought a DR120 and a 5inch exhaust RVK.
It's a bit too strong considering i don't have an intake fan. It's pulling in the sides of the tent slightly, so i feel that it's going to put pressure on the zips and the tent may soon develop small tears.

Do you guys have any tips on allowing air to come in easily in a closed up tent?
I can't keep the tent zips open due to light leaks.

much appreciated

How many of the 3 lower intakes are you using? Any?
If you're afraid they'll allow too much light in, you can cover the opening with a box, with cut-outs for the airflow. Just have the openings facing away from any bright light sources in the room.