HELP - Determining Water Line Drilling 125 Gallon Tank

[VSVP bet]

Hello,

Title explains it all, I know how to drill through my non-tempered aquarium, just need help with determining water line. Im using a modular marine 18, they provided me with a template. Should I try to get the overflow box as close to the rim of the tank as possible? I want the water line hidden underneath that black plastic top rim.

 

[miPapareef]

I have the shadow, and the limiting factor was the outside box cover hits the outside tank trim. So that sets the highest I could go with the holes. May be different for your overflow.

Anyways the flow rate of your return pump will determine how high up the water line is above the bottom of the overflow slots. If you are near the top end of recommended flow rate your water line will be closer to the top of the slots. Or near the bottom for low flow rates.

Here’s a pic of my shadow at about 800-900 gph with the water level 3/8” above the tank trim and roughly in the middle of the overflow slots.

 

[VSVP bet]

Sounds good, I just didnt know if there were issues drilling below the top plastic tank brace. Yours pics shows there are not. I want to rest the top of my overflow box as close to the brace as I can.

 

[miPapareef]

Right no issue centering it under the brace. I’d just make sure you can get the tops off.