I just got an 80 gallon with a hood to be my first salt water tank. P.C.Pondbuilder is a buddie of mine and has told me to build a sump.

I have a spare 30 gallon tank to throw under the stand. I am just curios about my design. I was going to use a large U that went to an over the top style filter I have in parts. The tubes are about 1 inch in diameter? I would then run plastic tube for an undergravel filter for the spillway, then probably some hose to go to the bottom tank. Then there is issues with the bottom tank. I have the basic ideas down. But how do you determin how deep to build the bottom tanks waterlevel? Do you just rough guess the water volume of say 4 feet x 18 inches x say two inches deep. That would be how deep the overflow tube would sit in the water, roughly two inches. Then determin say the 7.4 gallons of water that would run in the overflow system, in a poweroutage, would need to drain into the lower tank. Am I correct?

I also have seen there to be a "maze" for the water to run through, why?

In the return of the water to the tank, does it need to run through any sort of "spray nozzle" or would just having the hose go back in be enough?

Here is my crummy photoshop ideas.....

Hey newbie Welcome to the board, boy they will let anyone in here won't they.......I guess so I'm here.  You got the main Idea just make sure that you leave enough space so It dont overflow in a power outage. The "maze" Is to keep bubbles out, seperate macro's etc.

The drawing looks pretty good although you will need more than a powerhead to run water back up to the display and Instead of a sponge use live rock and run a little floss every now and then.

By the way Do you like my avatar

1. Under that sponge is going to be a "time bomb" of crap!
2. IMO, those type of sumps are not efficient enough.  Try separating your refugia from your sump and run two drain lines.  Then have the refugia overflow into the sump.  I think that works better.
3. If your "maze" isn't big enough, it won't help with the bubbles, depending on your flow rate.  There are better ways than baffles, IMO.
4. Why not drill your sump and use an external.  They last longer, IMO.
5. Welcome!

Hey PC is that on the PC you build ponds, or are there lines to be PC in pondbuilding? Yea avitar looks familiar....

Marcus, I understand that the sponge wasn't the best idea, mostly for noise. Maybee I'll drop the sump inlet JUST above the water, but would that work for poweroutage?

If I run refusia in the tank, and in the sump what would it matter? Can't you just add more refusia if there are issues with filtration? Isn't the live rock saposed to help too?

Nobody explained how to have the water re-enter my tank, so I will say this. I talked to a couple shops and they said I need a spray bar for surface agitation so I will run 1/2 inch PVC aross half of the tank across the back. I was going to run across the entire back, but was told I needed flow go half would be plenty and start a current. I think I will drill the holes at an angle to help with current.

I am kinda confused on oxygen in the water. I have read here that the salt water fish "need all the oxygen they can get", but yet we strive to get the air bubbles out of the water system. How then does the water stay oxygenated enough to form the vital oxlgen chain that will make the fish healthy?

First of all, its spelled "refugia". 

I do not like nor use spray bars.  I like to use lock line with a couple return lines so you can aim them better. 

I have never seen a fish go after an air bubble unless its during a feeding and they think its food.  I doubt they "breathe" air bubbles. 

Even if you drop the drain line below the surface of the water level in the sump, it may still make noise and pump air bubbles into your sump.  I back up the drain line on my tank with a ball valve so that no air bubbles get into my sump.  Plus its quieter because the drain in the overflow doesn't suck air with the water.  I also run only 25% of my water flow through the refugia then into the sump chamber.

For the record, this exact topic has been discussed a TON of times.  Use the search button and read some of the other threads about DYI sumps and refugias.

I agree with Marcus.  Fish can't really breathe bubbles.  Actually air bubbles are more difficult... better to say less effective, at providing O2 to the fish.  The gills really do need water to flow past the gills to keep them seperated (the reason fish can't live out of water).

Adam

"7.4 gallons" is a lot of water. The lines need to be designed so that only a few gallons of water gets siphoned back to the sump/refugia when the power goes out and also that the siphon is not lost so that the system starts back up when the power is restored. Are you aware of how to design that?

Marcus,

I did search the board before i posted this Q. I however did not get any answers to how to get the water back, air in the tank, or why you needed the "maze" in the lower sump tank.

You say you use "lock Line" to return the water to your tank. What is this?

So using an air pump doesn't really help with adding o2 to the water even though you see small bubbles? That would have to add some o2 to the water due to the molecules passing around to other molecules.(sounds smart) Thats how plants add o2 right?

Mark,

You quoted

 "when the power goes out and also that the siphon is not lost so that the system starts back up when the power is restored"

Well isn't syphon break the way you design these systems to be "fail safe" ? I can't get my powerheads or over the back pupms to start up half the time after turning off the power for whatever reason.  How do you design this system?

Thats  my original Q. I haven't got a clue. So Far I built it and it all seems to be cascading down to the two powerheads (804's)running it back to the tank. One is a spray bar and one is just a 5/8" hose.

On my "skimmer box" I got an old plastic cheesmo tank with warbled front from petsmart (old beta tank) and hung it with two uver the back powerhead clamps. Cut a few notches into the top and thought it would be fine. I am running a 1" outlet tube from the skimmer box to the sump tank. It keeps pulling water out of the skimmer box faster than it will fill. The box is roughly 16 inches across, 3 inches deep, and 12 inches tall. Should I drill holes in the bottom of the skimmer box? I like the idea of a skimmer, but don't get how to match the overflow rating with the sump rating. I kinda thought it would even itself out, but obviosly not....

Skyetone, if you are going to keep the sump and fuge together I would suggest one more baffle so you do not get a dead spot.  Maybe something like this...

Here is how I have the feed into one of my tanks (the 40g fuge).  I don't worry about a siphon break because the sump will handle the back siphoned water.

Here's how mine is set up...

Travis,  I really like that set-up.

Do you have any trouble with bubbles from the fuge dumping into the sump near the return pump?

Thanks Jon,

Do you have any trouble with bubbles from the fuge dumping into the sump near the return pump?  I did, what I had to do to correct it is put the return in a plastic bottle.  The plastic bottle deflects the bubbles from entering right in the pump.  A short baffle would be a better design.  It looks more like this.

I don't get the point in having a sump if you do not have the refugia in it.

"I don't worry about a siphon break because the sump will handle the back siphoned water."

What do you mean? And what exactly is a ball valve? Like a float?

Anyone have some stats to help with the skimmer box flow?

BTW thanx for all the help....

If you have a sump then I would recommend having a refugia.  Some people have a sump just to get their skimmer, heater, and other items out of their main tank.

" "I don't worry about a siphon break because the sump will handle the back siphoned water."

What do you mean? "  I don't know what Travis means either.

Ball valves are at any plumbing store including Home Depot.  They connect two pieces of plumbing (in this case it would be PVC) with a valve to reduce the flow from 100%-0%.  It is not a float.

What's a skimmer box?  Like an overflow box?

"I don't worry about a siphon break because the sump will handle the back siphoned water."   What I was tring to say is...  some people will drill a hole to provide a siphon break in the inlet.  -Sorry, I'm can't seem to explain this very well-

Why have a sump?  For several reasons.  First and IMO the most important is water movement and gas exchange.  The flow through a fuge is typically less than the flow through a sump.  Another as Marcus said is to get some equipment out of the display tank.  A sump also provides a great place to drip kalk, add your additives, etc. 

Here we go...  I have seen some people drill siphon beakes as shown here with the red arrow

The water will spray into the tank and if the pump stops the hole allows air in and breaks the siphon faster.  

"If you have a sump then I would recommend having a refugia"

A refugia? Isn't refugia the plant that you put into the sump and regular tank to filter with?

Yea I meant an overflow box, it skims the top of the water :D

Travis I don't get how drilling a hole in the bottom of the plumbing would help syphon break. Even if said hole had a tube that was JUST slightly higher than the inlet to the main syphon, would the syphon restart after the power was on and water was filling up again. I see my setup right now ALMOST does this. Starts to trickle down the tube but I haven't tested to see if it would go to full syphon again...

So much knowledge needed, so little time.....

skyetone - no, a refugia is a separate "sump" that houses algaes that filter the water.

I hole where Travis's arrow is will break the syphon if its the power is lost.  The diagram above is a return line, right?

Me too.

Sky if you would like to make a simple return I wouldn't even use a siphon if you take your main tank to home depot they will drill a hole in the top for you then you can just have an overflow that way you never worry about it all you need is a rubber seal and some PVC it's easy and foolproof  this way only excess water is sent to the sump (pump on water flows pump off no water flows) only what your pump sends up comes down just be careful you use a pipe big enough to handle the amount of water coming into your tank.  If you use 3/4 pipe from the sump at least use 1" for the return to the sump.  If you can't take your tank to the depot you could make a return tank IE you siphon water into a small 1/4 gallon tank hidden to the side or behind your tank then water flows out of that tank by a hole in the side of it just like is stated above.  You could make a simple one out of plexi-glass for $5 and save you all the hassles of overrunning your tank or sump in case of a poweroutage.  You may need to drill a hole in the pipe going from your sump to your tank so it won't siphon if power goes out.