# what size sump for my 75 gal.?



## danielle l. (Apr 14, 2008)

hello all i have finally upgraded to a 75 gal. was interested in building a sump what size tank would i need for my sump?


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## Mcdaphnia (Dec 16, 2003)

There is one school of thought, with some logic and facts behind it, that you should subtract the size of your tank in gallons from the number 5000, and that number should be the size in gallons of your sump.

In that other world, the one most of us live in, that just means the sump should be as big as you can make it, taking into serious account concerns of space, cost, and massive evaporation. I can usually pick up a scrap of pond liner at the garden shop for cheap. That makes a nice sump under the tank, supported with some plywood panels as needed. The advantage of the liner sump is that you can easily change its size and shape often without disturbing the plumbing, until you settle on your favorite configuration.


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## dr wethumb (Jun 22, 2008)

I had a 33 gallon sump on my 100 gallon tank but it was a pain because i wanted a jet so really had to pay attention to my waterlevel a 70 on a 70 no fuss no overflow rubbermaid bucket.you could swing a 20 gallon but i dont see the point on a 70 it can be anything that holds water.barrel garbage can etc.


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## zugbug (Dec 12, 2005)

heres a good link to determine the proper sump size. I have a 135g with a 20 gallon sump....no problems.

http://reefcentral.com/calc/sump.php

hope it helps.
zug


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## Charlutz (Mar 13, 2006)

A 20L is a cheap sump and the right size for ordinary applications on a 75g


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## Charlutz (Mar 13, 2006)

A 20L is a cheap sump and the right size for ordinary applications on a 75g


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## dreday (Oct 12, 2007)

a container that can hold 8.75 gallons and have .75" holes in the tray to move at least 300gph.


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## Mcdaphnia (Dec 16, 2003)

zugbug said:


> heres a good link to determine the proper sump size. I have a 135g with a 20 gallon sump....no problems.
> 
> http://reefcentral.com/calc/sump.php
> 
> ...


 This is to determine the minimum size needed to prevent overflow of water if the power is interrupted to the system, not the optimum size for maximum stability of water quality.


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## zugbug (Dec 12, 2005)

Mcdaphnia said:


> zugbug said:
> 
> 
> > heres a good link to determine the proper sump size. I have a 135g with a 20 gallon sump....no problems.
> ...


That is part of it but read the full article (actually this is part II of a 3 part article). I think you are confusing the meaning of "overflow"
Size

The general rule of thumb for the "ideal" sump volume is "as big as possible." Of course, there are some realistic constraints that must be applied. Normally, those constraints are based on the size of the area in which the sump will be installed. I've also heard a rumor that not everyone puts every dollar they earn into their reef aquarium, so perhaps there may be monetary issues for some as well.

If a typical installation is planned that locates the sump under the aquarium stand, then the useable area under the stand will dictate how large the sump can be. When measuring the available space for a sump under the stand, don't forget to take into account any space that will be taken up by other equipment such as external pumps and chillers. Avoid squeezing too much into this area, if possible, as it's best to leave plenty of room to maneuver around the sump. Equipment that is difficult to work on leads to an avoidance of fixing minor problems and doing regular maintenance which, in turn, results in major problems or unnecessary equipment failures.

So, bigger does not necessarily mean better. While the rule of thumb above states to provide a sump that's "as big as possible," there are some other considerations to bear in mind. In the previous article I mentioned that there are many benefits to increasing the total water volume in the system. However, it must also be noted that there are some minor detriments to that concept as well. A larger water volume also means that larger or more powerful equipment must be provided, such as heaters, chillers, protein skimmers, and UV sterilizers, all of which may impact budget constraints on the project.

The most important consideration is that the sump must be large enough to handle the aquarium in question. There are two considerations in this regard. First, the sump must be able to handle the drainage from the aquarium when the pumps are shut off without overflowing. To view an animation of this, click here. For this reason, the sump will always be less than full when the pumps are running. Also, the sump must have enough water in it to provide the benefits described in the previous article, and to avoid problems such as noise and annoying bubbles. This handy online calculator can be used to determine the recommended volume of a sump that will be necessary to handle the overflow from a given sized aquarium.


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## Mcdaphnia (Dec 16, 2003)

Zugbug, I hope someone needs your detailed explanation of what I summarized as "taking into serious account concerns of space, cost, and massive evaporation".

However it is not totally true that the ideal sump volume is "as large as possible". Practical experience with large systems has shown that once a system ( the tank volume added to the sump volume) reaches 5000 gallons, there is no improvement in water quality and stability by going to 6000, 100,000, or more. Of course getting anywhere close to 5000 gallons in my living room has been vetoed by my spouse, so for hobby purposes, not much difference.

I have seen the improvements local reef keepers made in their tank or system of tanks. Adding in one case, a 300 gallon and 150 gallon RubberMaid stock tank as sumps in the basement connected to the 265 gallon living room tank by pipes through the wall. Another guy had a concrete slab floor, so he jackhammered out a section of it, dug a hole about 4' deep, and used a pond liner to make his insane sump with a multiple tank stand bridged over it. Crazy guys but they had great reef! Obviously the exceptions to the rumor about money being a factor.


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## Charlutz (Mar 13, 2006)

McD, you are very knowledgeable. Been a fan of your posts and your generosity in helping people with questions for a long time. :thumb: Zugbug, I know you are also trying to help. But (there's always a but) can we agree that this almost theoretical discussion of the many factors that go into sump design isn't helping the OP who is clearly a first time sump user with a basic question of what size sump to get for a small tank? Can we just agree that a 20 or 30 gallon tank, preferably long and low and not high, is the right way to go and move on? Yeah, another size might be better if we're doing a refugium, sand filter, UV, etc., but that's putting the cart two miles before the horse.


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## Mcdaphnia (Dec 16, 2003)

Charlutz said:


> McD, you are very knowledgeable. Been a fan of your posts and your generosity in helping people with questions for a long time. :thumb: Zugbug, I know you are also trying to help. But (there's always a but) can we agree that this almost theoretical discussion of the many factors that go into sump design isn't helping the OP who is clearly a first time sump user with a basic question of what size sump to get for a small tank? Can we just agree that a 20 or 30 gallon tank, preferably long and low and not high, is the right way to go and move on? Yeah, another size might be better if we're doing a refugium, sand filter, UV, etc., but that's putting the cart two miles before the horse.


Good points, although I like the suggestion of making a sump with a bit of pond liner and some plywood squares so that the shape and size can be reconfigured from experience to suit the user.


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## zugbug (Dec 12, 2005)

Charlutz said:


> McD, you are very knowledgeable. Been a fan of your posts and your generosity in helping people with questions for a long time. :thumb: Zugbug, I know you are also trying to help. But (there's always a but) can we agree that this almost theoretical discussion of the many factors that go into sump design isn't helping the OP who is clearly a first time sump user with a basic question of what size sump to get for a small tank? Can we just agree that a 20 or 30 gallon tank, preferably long and low and not high, is the right way to go and move on? Yeah, another size might be better if we're doing a refugium, sand filter, UV, etc., but that's putting the cart two miles before the horse.


Well said. I agree a 20 or 30 gallon tank is the way to go. I dont think I want a home made pond liner sump in my house.


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## dreday (Oct 12, 2007)

i would say 10-20% of the main tank. and you want it higher than longer. with the height you can get more area for biofiltraion in the wet/dry section. which is the main reason people go with sumps. so a taller tower structure to stack media and filter pads is ideal. if the tower is half of the length than the other half would be for the equipment and extra water during power outages. if you look in the DUY section for sumps you can see some nice ones.

i believe there is one with a 29g tank and a 5g bucket. where the bucket was the media tower into the 29g, and it was above the bottom to leave room for extra water.


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## Charlutz (Mar 13, 2006)

I disagree that a taller sump is better. Long and low is my preference. Easier to fit under a tank and easier to work in for maintenance. The top of the tower does not have to be inside the sump. It can sit above it. The tower height is not limited by the height of the sump.


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