How clean is "normal"?

[coolhandgoose]

Well one problem I can think of is what happens if one piece of equipment fails. Let's say a return pump quits but the other one is still there, You're DT will drain a lot as your one return pump can't handle pushing the water volume back to the tank on it's own and possibly flooding your sump.
The other would be draining your sump if for some reason one of your overflows stopped working. I think redundancy is good, but with an overflow sump design, I don't think there's much we can do to make it bullet proof against equipment failure.

 

[Bifferwine]

If you use an overflow box, there are precautions you can take to ensure that the display tank doesn't flood, and that the sump doesn't flood. The overflow box can only drain as fast as the return pump is pushing water back up, so if the return pump dies, the overflow box will drain until the water level goes lower than its teeth. You need to simulate a power outage when you set the tank up, and don't fill the sump more than it can handle when you turn off the power. This means leaving about 1/3 of the sump empty for most people. To make sure the display tank doesn't flood, you need to plumb a ball valve on your return line to control the flow of the return pump. And you need to drill anti-siphon holes at the water level in each of your return lines to prevent a back siphon in the case of a power outage.

If you do these things, you won't have a flood. Overflow boxes take up too much space, and return pumps consume power and produce heat. I see no reason to have two of each. The chance of failure is so slim... The only thing I can think of that happens once in a while is if a snail clogs the overflow, then the display floods. But that only seems to happen with the u-tube style overflows. If you use another type, you should be fine.

 

[yote]

+1 Biff
When it comes to our filtration system,the K.I.S.S. method is the most effective.

 

[Kliman01]

Perhaps I'm not using the correct terminology...I'm planning on installing 2 of these:

700 gph Overflow complete kit - Glass-Holes.com dope aquarium stuff

Not the siphon-based over the lip type. I figured that it's only going to overflow as fast as one or both pumps can move the water, and should there be a power failure, the upper tank should stop flowing water into the sump fairly quickly....but yes, I would calculate the volume and leave room in the sump tank and test it out.

Also planning on using an APC SmartUPS 1500VA UPS to keep things running (at least for a few hours) in the event of a power failure. I've got several of them kicking around, so why not!

 

[Bifferwine]

Ahh okay. Depending on the size of the tank, it will be fine to have multiple overflows. Usually 4 foot long tanks have one, and anything larger has two, three or four.

 

[ggNoRe]

It's not really so much about the stuff floating around in the tank (although, crystal clear is nice there too)...it's the growth I see all over the glass at the LFS. I asked the somewhat knowledgeable kid that worked there if that was normal, and he's the one that told me it was unavoidable...figured I better double check.
This thread has pretty much made my mind for me...90Gal marine setup, here I come!

:bounce::bounce: Whoooooo!! You won't regret it! Such a fun and addicting hobby. Looking forward to see the pics.

 

[bjohanson1234]

Here is the easiest way to figure out how much water to put in your system. Fill it up, both main tank and sump. Main tank until it starts draining and sump about an inch or two down from the top of the rim. Turn on the pumps and let it run for a few hours. This will get most if not all of the air out of the plumbing lines. Then take a Sharpie and mark where the water level is on your sump. Then make sure you never fill your sump above that line. If power happens to go out, the tank and line will drain into your sump and will stop draining when the sump is an inch or two below the rim of the sump.