How to use a sump without drilling your tank

[Yodaob1]

Is there a way to Connect a sump to the tank without having to drill for bulkheads. Right now I have 155 gallon bowfront front tank set up with a full full canister filter. Been up and running for a year but looking to change out the filter to a sump four maintenance and easier changing the filter media( poly fill and Cabon). 

[Frank]

A simple, crude way would be to drill holes in a hang-on back filter.

[OceanTruth]

There are DIY PVC designs you can find on youtube. Back in the day I made one out of pvc, but later I just started drilling tanks. It worked great and never had a problem, but in the back of my mind I was always wary that it would lose its siphon and I would end up with a minor flood. I would always drill a tank if I wanted a sump again in the future.

Select Aquatics has a fairly complicated PVC design, just from the looks of it. Maybe it’s better at keeping its siphon? I haven’t researched that kind of thing in years, so I’m out of the loop.

[Will Billy]

I have never had a sump, but did much research on them. Sort of paraphrasing @OceanTruth, they do have overflow boxes that use a continuous syphon system to pull the water out as your sump pump pushes it back in. Again, not from experience, but just from simple research you have to #1 match sump pump flow to syphon flow, and #2 if your syphon loses pressure, or breaks syphon seal so to speak, there is potential for flood disaster. There are ways to mitigate this including adding a float valve that detects water levels and shuts off pump in the event something goes wrong. In my research of sump systems the most fail proof method i found was a top water skim method that still involves drilling a bulkhead in your tank. Maybe someone with actual experience can better help you out, thats just been what i have researched from other peoples experience. If you do go sump system, i have heard great reviews on the seamless sump system. @Cory had a cool video of a DIY sump system that flows sideways, instead of down. I found the video very interesting and informative. Here is a link to that cool little project.