I have a Whisper 40 and have the CO2
going into the intake pipe at the top. I drilled a hole just big enough for the airline and then put a little bit of gel super glue around the hole. Has worked great for almost a year. There is a way to shut it off at night. I used to do that until it just got to be too big of a hassle. You add a three way splitter in the CO2
hose and attach a balloon other the third stem. Use a rubber band and make sure it is tight and use a thick balloon. Add a shut off valve in front of the three way splitter. At night turn the valve off and the gas collects in the balloon. In the morning open the valve and the gas leaves the balloon. I did this for a long time and it worked. I just got tired of turning it on and off. Leaving it on constantly hasn't caused a problem.
Just keep an eye on it when you first renew the mix. I have two filters with CO2
lines in the out take pipe on my 29 gallon.