Yes I connected it to the top of the HOG via a short length of airline. I don't think it will connect directly as the outlet pipe would foul on it but I don't see why it wouldn't work if it was connected directly. I was already experimenting with airline in an attempt to reduce the noise so it was attached and I just connected it to the bubble counter. The loop in the airline may also help in silencing. Also I used the sucker the bubble counter came with to attach to the glass in the sump to secure it although you could secure it to the HOG. Depending how your sump or tank is made directly attaching the bubble counter may foul on a strengthening bar above it.