Humming noise in water pipes after installing an RO filter

We installed an RO filter at our office. Instead of using the provided saddle valve, we installed a tee at the end of the cold water hose where it attached to the faucet and reduced one of the outlets to fit the 1/4" compression fitting. Whenever the RO filter is refilling the tank there is a loud humming noise coming from the water pipe. It is possible the humming will stop if I use a saddle valve instead of the reducer on the tee?

 

Saddle valves are a disaster waiting to happen. I'd avoid using one. Not sure what is causing the humming. It may be normal with that unit. What is your water pressure? It could be higher than recommended for the filter. Rather than that T, they do make dual outlet shutoff valves. It might be quite easy to replace the shutoff.