[globaldesigns]

In my case, I have a 180G DT with a 105G refuge, the display has 2 overflows on either side with Standpipes. What this means is that if the return pump fails, only a certain amount of water will flow out of the main tank into my refuge. With the refuge, it isn't full, maybe half, so it has more than enough room for this display tank water in that case.

Also make sure to match your return pumps with your flow, or have valves so you can adjust this. When I first got my tank, I regretted it, the first night I had water flowing over the top of the main tank on my head. NOT FUN!!! I couldn't get things matched up.

Over the next few days all was good, but one night I couldn't sleep, when I went out to check the tank, it was just starting to again flow over the top of the display. I ran, swearing and opening all valves wide open....

After that I looked into durso standpipes. I made some put them in my overflows and I can say they have been the best creation I have done to this thing. All my valves (downward and upward flow) are wide open, so no more worries about overflows, and they also quited down the noise to nothing on the overflows.

If buying a used tank, maybe have it resealed, if buying new, buy from a reputable LFS and brand. If custom made, again have it made by someone that knows what they are doing.

I hope this helps some.