Instruct: Classify the given Amazon review into positive or negative sentiment.
Query: Poor Air Flow

I inherited a Blue Air 503. A couple of months ago I decided to up-grade to Smokestop Filters and I have to say, I was very disappointed by how much airflow I lost with the addition of the active carbon in the filters. I would guess that my CADR was cut in half, if not more. On fan speeds 1, 2 and 3, I can't even hardly feel any air coming out at all. Only on fan speed 4 does it seem to be moving any air, but fan speed 4 is far too loud for me. The top filter that lies flat, doesn't seem to have any air coming out even at the highest fan speed. I feel like I wasted the extra $50 on the Smokestop Filters. I have just ordered a new set of Particle Filters and I will throw the Smokestop's away.