Overflow for a 55 gallon

I'm planning on adding a sump to my 55 gallon non drilled tank. I came accross a spare 20 gallon tall that wil fit under my stand. I feel I have the correct understanding of how to keep some causes of a flood down by preventing a siphon if I lose power and causing the sump to overflow. The mystery to me is correct selection of an overflow box that won't fail or more correctly less likely fail ending up in my DT overflowing.

Reef Aquarium Filtration: Eshopps Overflow Boxes

currently I'm considering the eshops PF-800, CD-32886 . Would this be a correct size for a 55 gallon? and is this the correct style I need. also what size return pump would I need for this? if it matters for current flow I have a fluval 305 and 2 K3's. Looking for any and all suggestions, please help me do this right the first time.

 

With two K3's at 850gph each that puts you at about 30x tank turnover. I would shoot for about a 800gph return pump dialed down to about 600gph. This would put you in the 40x turnover rate for your tank. This IMO is the optimum range for most corals other than SPS. The Eshopps PF-800 is rated for 800 GPH so the pump should do very well with it.

What type of corals are you planning on keeping? Also how many GPH is your skimmer rated for?

 

I have a Octopus Extreme 800S Hang On Protein Skimmer that is rated for 100 gallons. I have no clue how many GPH it is rated for. I am not able to run it at the momment because I can't see into my tank when I do. Currently it is on the would be sump filled with some old water change water making sure it works right. It took over a month for this thing to break in. All the micro bubbles is what is actually driving me to get the sump done, I would prefer to have zero risk of flood, but actually being able to use my skimmer is trumping that.

I have been made aware that the larger versions of the same overflow that have 2 siphons which would seem to reduce my risk in a flood. Is my logic correct here? Is there any downside to using a bigger overflow and smaller pump? is there a better brand that works better?

as for corals, I would like to work my way to SPS's as they are my favorties. I currently have 2 diff types of zoas, gsp and a dead green monti that I am blaming on my broken heater for letting my tank get down to 67 degrees one night.

 

Your still on the right path than. I have never heard of a flood caused by proper use of an Eshopps overflow.

At first thought it would seem having two u-tubes would be a good safe guard. The problem with this theory is, if you use a pump rated to far below what the overflow is rated for the flow rate won't be able to push the bubbles through the u-tubes. They can slowly collect at the top and end up breaking siphon if not watched closely. If you use a pump capable of pushing the bubbles through both u-tubes and you loose siphon on one, the other won't act as a successful backup because the single tube won't keep up with the pump rated for two.

IMO, no. Most other overflows rely on lifter pumps. They're just another potential point of failure. Eshopps overflows rely on physics to restart. Physics doesn't fail as often.

The PF-800 should work perfectly for your tank than. It will push some decent flow into your tank making it as easy as adding one more power head when you start getting into SPS. A third K3 or maybe K2 would fit perfectly for this.

 

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as informative as this is it leaves me one question. What are you even talking about?

 

Uh, yea, as informative as that post was, let me try to help you out.

There's another type of overflow that CPR makes, I believe it's called a weir style overflow. Basically, you need to use an aqualifter pump or some other power head to remove air bubbles that accumulate. The style is much more flat and has much more surface area where the water flows through, but this results in much slower water movement through the overflow, thus requiring the pump to pump the air out. This method is effective, but it relies on another piece of equipment that can break, and it that pump breaks, the siphon will fail shortly after wards.

I have a 55 and used a U tube style overflow. I've not had any problems with it. I do check it daily and when I do water changes, I redo the siphon. The U tube style can actually have a fairly large air bubble without breaking the siphon. I have it where only about half the water that normally flows through it and it didn't break the siphon or cause my pump to run dry. I found that the U tube style works best when kept clean, so the water can move faster through it.

So in the end, both types can fail and there is no 100% with HOB overflows, but if you keep an eye on it and clean it, you shouldn't have any problems with either style.