First off, thank you for taking the time to read my thread. I could really use some help. I am relatively new to the hobby of saltwater reef tanks. I just recently bought a 72 gallon bow front tank with a 30 gallon refugium. It has plumbing already attached and an overflow box with 3 drains. Primary, secondary, and emergency drain. It also has 2 output lines. I will attach pictures so you can see the entire setup.
Okay, so on to my overflow issue...
My first attempt at filling the tank wasnt such an easy process, as the drains required some fine tuning to get the flow perfect. Nevertheless, some trial and error, I was able to get it flowing perfectly. I didnt feel comfortable leaving the tank running over night, so I decided to shut off the pump. The overflow box was empty, so as the water settled, I thought I was safe. That was my first mistake. I didnt think to close the ball valve for the output line and the output hoses were submerged underwater. So yes it caused a syphon and drained water, I woke up to the tank water level about 3 inches below where I left it and the refugium was filled to the brim and had overflowed. I drained out some water and decided to give it another shot a few days later.
My second attempt was last night. I filled the tank up like before and got it up and running with no issues. It ran for hours with no problem. Due to my incident a few days earlier, I didnt feel comfortable leaving it running overnight. So this time I shut off the pump, closed the ball valve, and even pulled my output lines out of the water. The overflow box was dry again, so there should be no way for water to get through the line this time, right? Wrong again. Woke up this morning to the tank level down 3 inches again and the refugium filled to the brim.
I am seriously at a loss for words. The only other thing I can possible think of is that there may be a small unnoticable leak into my overflow box, which overnight is filling up and going down my drain pipes. I really want to get this water thing down, because if I ever have a power outage, I dont want to have a mess in my house.
If anyone has ever experienced such issues or has some suggestions, I would really appreciate it. This thing is getting frustrating, as I dont know where the water could be coming from. If you have any questions, dont hestitate to ask.
Some pictures are attached...