HERBIE ON HOB OVERFLOW
 

So Ive been recently converted our large tank to a Herbie setup and it has done awesome! If anyone is thinking about I highly recommend it. We only had 1 overflow so the return had to come over the back, but its totally worth it. Anyways Ive decided I want to do this on our little tank as well. This tank runs a HOB overflow. In principle this should still work. I will be drilling into the side of the back box for my emergency, as high up as possible. I will also be rigging up a float valve to turn the pump off if things go sideways. I couldn't find any others who have done this so im guessing Im just looking for confirmation before I drill into my overflow. Based on my understanding of everything I think im good to go, but if anyone has anything to add or think about please let me know.

Im guessing no one has done this then lol. I tried it anyways. I drilled a hole in the side of the overflow for the emergency, I had to shave off the sides of the bulkhead so it fit in there. I drilled almost right at the top which looked right at first but I didn't account for the tank being slightly higher, in retrospect I would have put it a little lower. When it runs in full emergency the tank is full right to the top and it splashes over a bit, not major but not perfect. It seems to run as a herbie should, but needs readjustment after a water change or a power out. I don't recommend this setup (or HOBs in general) but for an established tank that you don't want to move it seems to be working out.

Im using an eshopps HOB and have thought about doing this but couldn't really find anyone else that has attempted it. I would like to see pics of what you have done.

I have the eshopps 800, ill try to take some pics tonight

One week update, works awesome. Takes some time to reset after water changes but that was expected. Although I haven't had to use the second pipe I still am thinking about drilling it lower.