Cali Kid Corals

Overflow and Sump Question (thinking about adding)

georgec

georgec

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Hi all,

Thinking about adding an overflow and sump to my 29G have a couple of questions.
Currently have a 29G, 2 Maxis (600&900) and a Seio 620, Remora skimmer.

Reasons for adding sump:

  • [li]Provide space for a refugium[/li]
    [li]Get rid of some of the junk in my tank (heater, skimmer, maybe one or two powerheads)[/li]
    [li]Increase overall volume to better stabilize parameters (though they have been ok)[/li]

So here are the barrage of questions:
-Is the threat of flooding as bad as everyone makes it out to be in the event of a power failure? What are people's experiences, and
-Any recommendations of the best overflow? I was looking at the CPR. I'd like something that is relatively quiet, but more importantly reliable. If it's going to sound like a flushing toilet all the time, I probably will opt to wait.
-Any difference between U-Tube vs. continuous siphon types?
-Recommendations on a return pump that is quiet, reliable, and produces low heat?
-How do you size sump flow to the tank? The smallest overflow I saw was 300 GPH (10X tank volume) - is that just right, too small, too big? Could I go 600? (My thinking is the more flow to the sump, the more powerheads I can get rid of in my tank)
-How do you size the return pump? I assume you match to overflow rate, but what happens if it is too low or to high? Do the overflows flow slower/faster depending on the amount of water returning to the tank?
-Silly question - with the refugium, will the pods etc. make it back into my main tank. I assume some of them flow out of the refugium and get sucked through the pump to the tank. Hoping this will allow me to perhaps add some other types of fish.

I am thinking of the following set-up:

- Overflow
- 15 or 20H aquarium with baffles siliconed in place. Room for refugium, and eventually an upgraded skimmer.
- Return pump connected to two return nozzles or perhaps a spary bar of some kind.

Thanks all for the help!
 
-Is the threat of flooding as bad as everyone makes it out to be in the event of a power failure?
Well depends, a properly maintained/designed system won't have any such problems. Things you need to look out for are bubbles in your siphon, that would be the largest issue. And making sure that your sump can handle the the reverse siphon water that WILL go into your sump in the case of a power outage, translation, however low in the tank the output is, calculate the amount of water from that point to the top of your tank, because that WILL go into your sump. Some people suggest holes near the top, but you need to maintain those holes though as they will eventually get gunked up.

-Any recommendations of the best overflow? I was looking at the CPR. I'd like something that is relatively quiet, but more importantly reliable. If it's going to sound like a flushing toilet all the time, I probably will opt to wait.
CPR is fine, especially if you're going to pay for it, which I would recommend since you're asking these questions seem you don't quite got the mechanics down. The best overflow however is one that does not use a siphon, drill your tank... however a HOB one can be sufficient if you dont want to modify the tank (I don't think I would ever suggest anyone go this route though). As to the toilet sound, a properly sized return will usually eliminate the most severe of gurgling, however there could be some additional sound, in which case make a standpipe of some sort to deal with it from PVC after the fact. Test whatever you have first then see if you need it.

-Any difference between U-Tube vs. continuous siphon types?
Except the cleaner look, no. However the CPR ones come (used to come?) with a nipple at the top that you can hook to a powerhead in the tank with air hose to periodically pull any air out that get's trapped/starts it up should the siphon break.

How do you size sump flow to the tank? The smallest overflow I saw was 300 GPH (10X tank volume) - is that just right, too small, too big? Could I go 600? (My thinking is the more flow to the sump, the more powerheads I can get rid of in my tank)
If the price isn't too much different go bigger. The overflow won't dictate how much water flow you'll get, the return pump would, those numbers just tell you how much they can "Safely" handle.

-How do you size the return pump? I assume you match to overflow rate, but what happens if it is too low or to high? Do the overflows flow slower/faster depending on the amount of water returning to the tank?
Well first do NOT match the overflow rate, the great thing about overflows is that they will continuously adjust to the flow rate pushing back into the tank as long as it does not exceed their capacity... if you put a little dribbler of a pump on, the overflow will only let that much water go in (try to google some overflow pages, maybe melevsreef, they explain the mechanics of how they work). Translation, do not pump more than the thing can handle and you'll be fine. Now after that the size of the pump depends upon your desires for the tank, I'm really weary about putting a large pump with a siphon overflow personally. I like a moderate/low flow through the sump, just so the skimmer can pull more, however your HOB skimmer that just removes that equation. So just keep it under the capacity and you should be fine.

-Silly question - with the refugium, will the pods etc. make it back into my main tank. I assume some of them flow out of the refugium and get sucked through the pump to the tank. Hoping this will allow me to perhaps add some other types of fish.
Your pump may kill a good portion of them, however you can be assured some will make it back.
 
George - if you would like you can come over and check either my work's tank or the one's at home. I can't say I'm that great in answering all the questions in writing.
 
Thanks for the answers.

SFSU, I did look at melev's yesterday and it helped answer some questions, but I'm dense, still a newbie to reefing. So it takes a few tries. Regarding overflow vs return pump, one more question. If the pump is too undersized vs the overflow capacity, will the overflow start and stop? Or just flow slower?

Also, I have a HOB skimmer right now, but am thinking about upgrading to a better in-sump model once the sump is built and seems to be stable.

Eileen, I'll find some time to take you up on your offer. I'm a visual person, and it helps me to see first.

Elite, I think the CPR has a nipple to hook a tube to a venturi powerhead or pump to keep out bubbles/maintain siphon. However, if anyone has had problems even with this setup, let me know.
 
Also you may want to think about putting in a fail safe. I just ordered a ATO from autotopoff.com but am not using it for an auto top off. I have two tanks hooked up to a single sump. Both with continuous syphon overflow boxes. I ordered a double ATO and am gonna put one in each tank above the water level. The ATO will be hooked up to my return pump and if the water gets too high in either tank the return pump will shut off. I asked them at autotopoff.com if it would work in this application and they said yes. They said it would be fine for continous use.
 
I hear the same thing Phong. I personally think that adding another pump is ridiculous.

I drilled siphon breaks in my return lines on both tanks at home.
 
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