5kg Co2 tank empty after 5 days, normal?

I run a DR240w secret jardin tent. (240cm x 120cm x 200cm).

I set up CO2 about 5 days ago. and the 5KG tank i bought is already empty.

I run at 1,000ppm, with ambient air being about 350 in my area(urban).

Its a sealed tent, only leaks i can think of are zips, a couple of tiny tears(1-2mm), and positive pressure from the ducting/cooling of lights (tiny pin pricks in foil ducting).

The controller operated the tank about 4-5 seconds every 4-6 minutes. Regulator is 0.17liter

Is this normal to use this much gas so quickly? It'd cost a fortune to replace a 5kg tank each week.

I appreciate any help.

Ive been doing some math and it seems like my tank emptied way too quickly comparing to other diaries ive read.
The ppm range was staying 950ppm to 1050ppm so i dont think it was releasing it too fast.

Maybe my tank wasnt filled properly by the guy at the shop.