Homemade sump for a 180 gallon tank

[KRGilley23]

Hello all,
I am currently in the process of acquiring a 180 gallon tank. It has two corner overflows. This will be a freshwater set up. I have read that you need to have enough sump for at least 1/4 of the tank size. Is this enough? I was thinking maybe I could use a 55 gallon for the sump. Any advice getting started is greatly appreciated. Thank you.

[Colin_T]

The sump needs to be able to hold enough water for the return pump (located in the sump) to work properly, and for any water that drains out of the tank when the power is off. I like sumps to be at least half the size of the main tank so there is plenty of space for the extra water draining out of the tank. If your tank loses 100 litres when the power is off, the sump needs to hold that, and the water that is already in the sump. If the sump isn't big enough, it overflows when the power is turned off.

---------------

I'm not sure why the tank has 2 overflows. Most tanks have an overflow at one end and the input at the other end so the water flows through the tank. Two overflows isn't a big issue, there's less chance of one blocking up, it's just overkill in my opinion.

---------------

Return pumps need to be able to pump the tank's volume several times an hour at the highest point of the tank (top of the tank). If the top of your tank is 5 foot above the ground, the pump needs to be able to pump the tank's volume 3-5 times an hour at 5 feet high. There should be a flow chart on any water pump and it shows how much water is pumped at different heights.

[Andy Sager]

Originally Posted by KRGilley23

Hello all,
I am currently in the process of acquiring a 180 gallon tank. It has two corner overflows. This will be a freshwater set up. I have read that you need to have enough sump for at least 1/4 of the tank size. Is this enough? I was thinking maybe I could use a 55 gallon for the sump. Any advice getting started is greatly appreciated. Thank you.

" I have read that you need to have enough sump for at least 1/4 of the tank size." I'm not sure where you read this but this is not correct. The sump only needs to hold enough water so that the return pump doesn't suck air while running and it can hold all the water in the drain lines should the power go out so the sump does not overflow. In my 75 gallon tank, I ran a custom sump that only held 10 gallons of water so it's not about the gallonage. Things to consider about a sump: 1) what is going to be inside the sump. More often than not, a wider tank is more beneficial than a taller tank. If your biological filter is going to be in the material in the sump, you need to have enough material to support the bioload in your main tank. 2) Is the return pump going to be directly plumbed into the sump or is it going to inside the sump. 3) What kind of material are you going to use to hold the bacteria bed. (i.e. ceramic rings, filter pads, bioballs)
Once you know these things, you can start to determine what size to use. Truth be told, the bigger you go, the more water volume you have within the "system" which will help delay the disintegration of water quality in the system. For me, I would use a 40 breeder over a standard 55 gallon tank. No need for the extra height of a 55.

I use a very simple method for preventing sump floods: Start with an empty sump. Fill the main tank to the point that the water starts to flow into the drain lines to the sump then stop filling. When the water stops dripping, fill the sump to the top ( or just below) and turn on the return pump. Once the water is flowing back into the sump, mark the sump at the water line and never fill the sump higher than that mark. If the power goes out, the water can only go as high as it was when you started. The only way your sump can flood with my method is if you have a leak in your tank that is dripping into the sump.