Gate valve needed big adjustment

[jdpeters]

So I came out to my living room with my tank and heard a substantial rushing water noise. The water level in the overflow box dropped a few inches inexplicably, it wasn’t gradual. Any idea what would cause this? I was tinkering with the tank earlier in the day but haven’t touched it in hours. Is it possible there was an air bubble in the system that would cause that?

Here’s an unsolicited picture of a naughty cat that got caught in the the rain.

 

[jdpeters]

Hope someone catches this. I just realized this happened 2 days ago and unfortunately I was away out of town at work. The water level in the over flow box suddenly dropped and my poor wife was left home with tank just chugging the heck out of the water. Nothing had changed. I’m thinking the overflow is getting air built up because of how far the water has to drop on the internal side of the box, major design flaw.


I could raise the water level in the over flow box a bit higher but I’m afraid of it flooding
Anyone know why every few days it needs huge adjustment?