This is the overflow of my second cement wall tank. 1,000 gallons an hour would flow over this and down the corner overflow to the sump below.
The corals growing here enjoyed the water-flow and the high intense light of the 400 watt Metal Halide light that was about foot and a half above it.
There was a total of 2 lights making a total of 800 watts of light. The tank was 120 gallons, 4 foot by 2 foot by 2 foot.
This is the overflow of my first cement wall tank before the bottom cracked. The right side also cracked before the bottom cracked, but it sealed
itself up, and did not leak. I had two 175 watt Metal Halide lights over it. And 1,000 gallons per hour of water going over the overflow. The
tank was 120 gallons, 4 foot by 2 foot by 2 foot.
A closer look at the second cement wall tank overflow.
A view of the underside of the overflow of the second cement wall tank. You can see the whiskers of the 2 cleaner shrimp hanging upside down under
This is the grid in the second cement wall tank overflow to prevent larger items including fish from going down the overflow. Egg crate lighting
panel cut to size works great for this, but I made this out of portland cement instead. The water is turned off so that it can be seen easily.
It is held in place by silicone sealant. It is designed so that it rests in place on the fitted silicone, but is easy to remove for cleaning
and maintenance. The corals growing on the overflow also do a great job of keeping things from going down the overflow.
The same picture as above, but with the water turned on. The whole system had only one water pump. The water falling down the overflow powered
the protein skimmer in the sump.
The same overflow with the portland cement cover and limerock sitting on top.
Another picture of the overflow of the second cement wall tank.
This is the overflow of the first cement wall tank. Notice the fire coral frags. They grew very fast there, and would cover anything in their way
including air bubbles.
This was an earlier tank. It was 30 gallons. It later became the sump for the first and second cement wall tank. This was originally a salt water
fish only tank that I started converting over to reef. what you see here is a portland cement tidal pool that sat on top of some large coral
skeleton and the water that was pumped into it overflowed into the tank. There were two anemones in the tidal pool, and some small corals growing on the
outside of the pool. It had a single 175 watt Metal Halide bulb over the tidal pool which was in the center of the tank taking up the back half. If you
look closely you can see a jelly mass hanging over the overflow. It's an egg mass from a spaghetti worm.
More pictures of the second cement tank overflow. This view is from looking inside the tank. At the left of the picture is the back wall of the cement