Quote:
Originally Posted by Noobeef  OK. Here’s my thinking. I found a nifty looking gadget (you’ll have to tell me if it’s a good product/company or not) that skims as it overflows. Here is the LINK for the gadget. Now it says it will not lose suction and let the tanks overflow in the event of a power outage. I’m a conservative person by nature, so I will want a backup plan. Now for my crude, Microsoft Paint diagram and what it is supposed to be saying. 
The sump at the bottom is a 10 gallon aquarium. I figure I will fill it up to around the 4/5ths mark. In the event of a power outage where the O/F unit continues to siphon away, there would be 2 extra gallons room in the tank and plastic container below it to catch any overflow. By the time the sump AND the plastic container are full, the main tank should have lost enough water that the O/F unit can’t suck the water up anymore. In the event of siphon malfunction, I will place the return pump near the top of the water line so it can only overflow the main tank by a gallon at most. I can live with 1 gallon of overflow if it came to that. Once again, this unit is supposed to be overflow proof, but one of the reviews from the customers said their unit did cause an overflow. Is this a good backup plan, or are there fundamental problems involved with my thinking?
Also, if this is a worthy plan, what the heck do I put in the sump? Live Rock? What? I feel like putting the lone heater in the sump is a bad idea. If the return pump OR the O/F unit have something go wrong, the water turns cold and everyone dies.  I may put a second heater in the sump in order to have two in case one goes. So what do you think of my diabolical scheme? |
I haven't read all the way to the bottom yet so some of this might have been said so far.
If you're using an overflow box (which is not a siphon) the only water that will drain in a power out is what is in the tubing and the outflow of the little box to the top of the standpipe. I'd hope thats less than 1/2 gallon really.
You can make a good overflow yourself from
pvc pipe. Do a search on some other sites for
DIY PVC overflow. The idea here is the overflow stops at the desired water level of the display tank. When water is returned from the
sump (raising the water level) the excess is taken out by the overflow box. If the pump stops, the water level won't rise.
Conversely, if you have a hang-on-back (HOB/HOT) powered filter with a drain in it - that creates a siphon that will pull water out to the first air escape hole in the downtube (part that sticks into the tank). Therefore if you go with this method what you want is a 'siphon break' - two small holes drilled in the plastic tube 1/2" below the intended water level. When the tank drains via that tubing, once the water level reaches those holes air enters the tube breaking the siphon.
As far as what you want to put in the
sump. I divide the
sump into three chambers with partitions that reach about 2/3's up the height of the tank. Have one line coming from the drain/overflow and then Y it off and put gate valves on the two lines after the Y. Have one line draining into chamber one and thats where you'll put your
skimmer. Adjust the valve on this line so you get about 80% of the drain's volume flowing into chamber one. Once the
skimmer processes this water, the outflow of the
skimmer should drain into chamber three (the return.) to be pumped back into the display tank.
Drain line 2 will get the other 20% of the flow and drain into chamber 2 (the
refugium!).
Flow in this 'fuge should be gentle but present. Here you will have a thick layer of live sand and chunks of
live rock. I would also add a ball of cheatomorphia
macroalgae. These components are natural biological fiiters and also provide a place for the tank to grow it's own live food. (A good thing!) Chamber 2 will overflow the partition into chamber 3 (the return).
Chamber 3 (the return) will have your heater and return pump in it. The pump needs to be strong enough to raise the water from the
sump up into the display tank and then create some turbulance (water movement).
You would probably want to add a second, stand alone power head in the opposite corner of the display tank from where you have the
sump return to create some cross currents.
Lighting is another thing to look at - we can go into that later however it looks like you have some great advise here already.
Jeff
icon under their name to add to their reputation. 
