Hang Over the Back or HOB overflow boxes obviously aren't anything new to the aquarium hobby. Simply put, if you (like myself) don't yet have the luxury of an internal overflow to circulate the water down to your sump, then a HOB overflow box is an affordable and effective alternative to avoid drilling holes, installing bulkheads, and gluing together PVC. Do these things ever fail, you ask? Absolutely! And I just learned this first hand...
Alright, blah blah, how did mine epic fail? Well, I hadn't touched the thing in months. The last time I even messed with my overflow box was to install the Stockman standpipe I made. Freakishly overnight, my overflow when rogue and two of the acrylic sides came apart at the seams. Wham! 3-4 gallons of water dripped out of my tank overnight. Luckily, it didn't split all the way down the seam, just about 3/4 of the way which allowed for a drip instead of a pour. And I must have had a guardian angel because I just so happened to have a thick towel on the floor behind the tank that I had forgotten about from my initial testing of the plumbing. Don't get me wrong, my carpet still got flippin' soaked, man!
First, before I get into how I fixed it, let me share with you a couple of ways to either mitigate the risk or avoid it all together. Either A: Have an internal overflow instead, or B: Reinforce the daylights out of your existing HOB unit. Acrylic is certainly not invincible so add some extra bonding material to the seams, 100 MPH tape, or whatever you've got to do to ensure an imminent flood is not in your future. It's not fun, guys! Not fun at all! Hmmm, maybe I need to invest in a shop vac.
I had a few options to include either repairing it or having a new one overnight shipped! Well, to avoid too much down time with the filtration, I chose to revive it. Superglue on the outside seams, silicone on the inside seams, 100 MPH tape, and about 9 hours worth of drying time, and I decided to give it a go. It worked! (And has continued to work without any signs of budging)
Lesson learned, these overflow boxes might seem durable and indestructible, but rest assured they can definitely cause some huge problems if they fail. I can't wait til my next build has an internal overflow! (Spoiler Alert) At least then if it becomes dislodged from its bond, it won't end up on the floor. Again, I'm not discouraging the use of HOB overflow boxes, but please be mindful of what could go wrong and have a plan of action in case it does turn for the worst. I hope this article has served its purpose in preparation. Also, stay tuned because I've got plenty of content and some opportunistic surprises coming soon! As always, thanks for reading and feel free to comment, like, or share below!