Importance of overflow emergency drain?

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slippery slimecoat

slippery slimecoat

Polypterus
MFK Member
Jan 26, 2012
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New York
I'll soon be setting up my first tank with a sump. I'm getting a 150 that's drilled with 1" and 1.5" holes. I've pretty much already decided I will do a herbie style overflow and bring my return up the back side of the tank with pvc. I really like the idea of the extra flow by using the 1.5" outlet as my main drain. But that makes my emergency drain smaller than my main. Are the odds of the main getting completely blocked and having to solely rely on the emergency drain really that great? Would it be completely foolish to use the larger outlet as the main drain?
 
I have been using drilled tanks for many years and never had one clog. Unless you have a dieoff of little fish or a plant die off, what can clog it? The answer is nothing. Dont worry about it. I'm sure someone will tell me I'm wrong.
 
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Did you ever burn up an HOB or cannister because it clogged? If you did you need to pay more attention.
 
rodger said:
I have been using drilled tanks for many years and never had one clog. Unless you have a dieoff of little fish or a plant die off, what can clog it? The answer is nothing. Dont worry about it. I'm sure someone will tell me I'm wrong.
Click to expand...

Pretty much what I was thinking. But since the sump is new territory for me, thought I'd ask. The overflow will have a cover that should help keep fish out, and the smallest fish will be filament barbs that are 4" at the moment. I won't be keeping any plants in the tank.

On the flip side of the discussion... I'm thinking of running a canister as well to run my UV, and have circulation pumps. So the extra flow from the 1.5" drain isn't necessarily a necessity. But the main inhabitants will be clown loaches and I'm sure they wouldn't mind the extra flow.
 
rodger said:
I have been using drilled tanks for many years and never had one clog. Unless you have a dieoff of little fish or a plant die off, what can clog it? The answer is nothing. Dont worry about it. I'm sure someone will tell me I'm wrong.
Click to expand...
X2 I have to agree, I've never had one clog either. I guess it's better safe than sorry...
 
I may have mentioned in your earlier thread, put a strainer on the primary drain, this should help to reduce the chance if clogging. Also, although you're primary is 1.5", it will likely be closed off a bit with a valve to match the return flow and/or control the water noise. You should leave the 1" wide open so it should be ok if you want to use that as you trickle stand-by.

On a side note, with the size of primary drain, sometimes the overflow wall , weir, becomes the bottleneck to flow. Personally mine has never clogged either and I have a third dry standby. Mu bro in law has clogged before in his reef tank - but he didn't have the strainer either.

It's one of those things that we can say doesn't happen until it happens
 
I had similar thoughts and worries. I have a 150 tall set up with a 40b sump. I designed my sump with these worries in mind, and was lucky I got it right the first try (I expected I would need to tweek some things).

My sump has three sections, making three levels. The tallest is where the water first enters and goes in the sock, higher because it stays quiet this way. This flows over the divider into the middle section which has two parts. The water goes into the first section where I have a moving media bed of mini bio balls held in that section by course, large pore gutter foam at the bottom. Water then travels through the lower middle section where I keep ceramic stuff. It finally goes over a divider and down into the last section where I keep the heater and pump to return it to the tank.

If I turn off the power, the water in the tank will drop into the sump until it drains to the top of my pipe in the overflow box. The entire tank drops about three inches, and the sump fills almost to the top at that point. The sock is still above the water level keeping the waste out of the sump. It literally can't flood my house.

If the pipe from the tank to the sump got clogged somehow, the pump is located in the last section of the sump which also has less water than the other sections. With no water coming into the sump, the only water being pumped back into the tank is that last chamber with the pump itself. The pump can push all the water in that section up to the tank and the tank has about 3/4" before it would overflow from the top when the pump can't push water up anymore. It can't flood my house here either.

Unless someone came in and added water to the system when it was clogged or turned off, it wouldn't be able to flood anything. Before I did this I really worried about it, but I've tested it so many times between turning off the power to rearrange, change the sock, and just losing power in a storm, I no longer worry about it.

I use two 1" intake pipes to my overflow box, then I took the 1 1/2" pipe down to the sump and narrowed it to 1 1/4" with and adaptor. The change in the flow keeps it quieter.
 
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Below is a 1.5" PVC overflow after a cichlid went on a ti-raid one night.


soon after, I switched to these, and even after these were installed, became one of the first things I checked every morning.
 
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duanes said:
Below is a 1.5" PVC overflow after a cichlid went on a ti-raid one night.


soon after, I switched to these, and even after these were installed, became one of the first things I checked every morning.
Click to expand...

Is that inside the tank or the overflow box? My cichlids are thugs too!

@OP: When I read the thread title, I figured an emergency drain was going to be installed in your sump so as not to overflow if the power goes out or a pump dies, etc. I think I read this is your first sump so I would advise you to make sure that your sump does not overflow when the pump is off. It is a common beginer mistake and wet floors are a pain to deal with. GL with your project.
 
The overflow in my tank above has an elbow, and is in a drilled tank. I always drill all my tanks in one of the smaller end panels.
Like this one on the left below. (not the same tank, but drilled the same way)
 
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