plumbing dilema

[Basile]

This is my drain set up, on both tanks, two herbies.My modifications are made to make the emergency pipe silent. At 1/2" over the water line the emergency pipe is no longer the daily constant gurgle occasional noise maker. The water has to rise to use that pipe, which mean if it uses it , its an emergency and not a daily anoyance. It become an emergency pipe, then you check it out and resolve the problem. Both main drains are at 6" under the water lines with strainers, checked every week in routine inspection,and both have spears gate valves fine tuned to create a syphon. The emergency pipe stay open to be noisy if used and alert me that something is wrong.