The lesson learned was keep your return lines higher up in the water for those just in case moments when your siphon breaks are plugged.
I was doing my normal water change, turning off the return pump and siphoning from the DT. While I was futzing with the pump from the mix barrel I heard a crack from behind me, I turn around to look at my Sump fearing the sump was blowing out, it's a 55 gallon acrylic and the water was an inch from the top (normally 7 inches), the tank was bowing way out and the bubble baffles were popping their seams. It had stopped an inch from the surface so no real damage done but I have adjusted my returns to be higher in the water after cleaning out the pin holes that are supposed to break the siphon.
I've been doing this for 2 years now and this has never happened.
Now to figure out whether/how to repair the seams or build another sturdier sump.
I was doing my normal water change, turning off the return pump and siphoning from the DT. While I was futzing with the pump from the mix barrel I heard a crack from behind me, I turn around to look at my Sump fearing the sump was blowing out, it's a 55 gallon acrylic and the water was an inch from the top (normally 7 inches), the tank was bowing way out and the bubble baffles were popping their seams. It had stopped an inch from the surface so no real damage done but I have adjusted my returns to be higher in the water after cleaning out the pin holes that are supposed to break the siphon.
I've been doing this for 2 years now and this has never happened.
Now to figure out whether/how to repair the seams or build another sturdier sump.