A few days ago I noticed that the water level in my main tank was way high. After investigating I determined that a big clump of algae dislodged from the inside of my overflow (the part inside the tank) and got stuck against some of the holes in the HGB. The water level in the overflow rose and caused the tank level to rise. This caused my sump to empty and my pumps started blowing microbubbles in the tank. These bubbles ended up collecting in my siphon tube between the overflow boxes because the flow slowed down dramatically. When I noticed this my tank was within a half inch of overflowing and my siphon tube contained a huge bubble that was also blocking half the pipe.
This was the second time this happened in about two months. When I got home tonight I noticed again that the water level in the overflow outside the tank was rising again. Another big piece of hair algae was trapped. I could no longer ignore the warnings the HGB had to go or get modified before I came home to a flood.
After pulling it out I noticed that the overflow really wasn't all that loud. I then got a new piece of PVC for a stand pipe and cut it so it was just lower than the height of the wall in the overflow. By using a stand pipe I eliminated the noise of the water crashing over the wall in the overflow down to the drain.
It turns out this is all I needed. The overflow is just as quiet as the HGB was and I don't have to worry about algae clogging the drain holes and causing a flood. Now, I'm not knocking the HGB design. Perhaps the holes I drilled ino it were just too small. But if the simple PVC standpipe does the job just as well why should I make something that is more complicated and has a higher risk of failing?
It would be really hard for anything to get stuck and block the hole at the top of the simple PVC. Perhaps my overflow is quiet since I don't have a huge amount of flow, I'm just using two 802 powerheads for my return pumps.
So what is the lesson here? I determined that I needed the HGB even before I actually tried my tank without it or trying the simplest solution first. Always try the simplest solution first.
