***David - Heres how its configured now.
The left overflow has both the original 1" drain and the intended 3/4" return being utilized as a combined drain for the Sequence Dart, both with homemade Durso pipes. This water then flows thru the back pane near the bottom, for a three-pronged sprayrack that resembles a pitchfork, to raise the rocks up a bit in the middle of the pile.
The right overflow has the 1" drain for sump, and the sole 3/4" return.
***Thomas - I choose this because it allow more flow thru the two existing holes. Dursos in an overflow cannot match a submerged intake. Aesthetic is also part of my reasoning.
I will be adding strainers to the existing bulkheads in the overflow, with no riser.
I had the 2 drains combined, with a 1.5" "T" mounted vertically directly under the 1" drain hole, with 3/4-1.5" and 1"-1.5" reducers in it to accomodate the smaller drain pipes. The water form the 2 drains combines in a 1.5" "T" and falls thru 1.5" pipe until the pump, so there should be no bottleneck effect where the drains meet. Yet I could only have the pump at half speed or cavitation would occur.
***Graham - The outer overflow still has conventional teeth at the top, but it also has two rows of tiny vents to let water in from near the bottom. The inner overflow is solid and watertight and doesn't have these vents, and is at the same height as the bottom of the outer overflow's teeth. The inner wall is what became dislodged.
I agree with the silicone curing part, I don't want that.
I will keep the small riser idea in mind, and try it if I feel the strainers get clogged too fast. Thats good thinking.
With the stagnation, I have the same scum of the surface. I assumed not a good sign.
There isn't really any detritus in there, I have been running a 2 1000 Micron socks for a little
while instead of 1 to see how much gets past the first one. Not much.
As of now, there are 2 Sedra 3500s @ 350gph for the skimmers, and a 700gph return running at full speed to match it. But the Dolphin return pump has begun to shock me once in a while, so I'm upgrading to a 950ghp Mag pump. The one inch drain will accomodate the Mag pump pretty well, at 6-800gph, but I feel that a two-ended LocLine out of one overflow isn't very useful since its too close to the corals and two strong to point right at them. So I'm intending on a 3/4" Seaswirl instead, and I may as well get as much flow from I as I can, since my new Mag will match it's 950gph capacity. I need the second drain to do this, and a little extra water over the teeth of the remaining overflow will help make up for the lack of one, as far as
surface skimming in concerned.
Joe
That's as long as the "underflow" will allow as much water to pass as you want to move. You might have to clean the strainers more often at the bottom of the tank, though - unless you put them up on a few inches of PVC...
