Need help with overflow plumbing

[Ryan_Lap]

Ive had my tank running for the past 3 years with the setup below. Ive never had it fail and it has generally worked well. Its running a stockman pipe. Its recently come to my attention that my setup may not exactly be "fail safe" and if the primary would become plugged for any reason (eg. snail) it would overflow. Im now worried that the tank may eventually overflow and I cant really have that happen. Any suggestions on how to make this setup with the current plumbing fail safe and silent? The back of the stand is enclosed with only a hole to access the one ball valve and changing the plumbing completely is not an option unless I empty the tank. which Id rather not completely. Any insight appreciated.