# Converting Fish Room to Central Filtration



## MoggaDogga (Jul 29, 2008)

I'm looking to expanded my fish room (converted garage), currently I have 35 tanks all using sponge filters running off a large Medo air pump. All tanks house tropical fish and the room is heated not the tanks, the total water volume is 1100 litres. I want to expand to more tanks, I've done a rough plan and can fit up to 3000 litres in various size tanks, the largest single tank will be 400 litres.

With these sizes in mind it wouldn't be practical to use sponge filters, so I would like to convert part of the room (if not all) to a central filtration system.

Has anyone any advice on setting up a central system of this nature?


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## nick a (Apr 9, 2004)

With 35 tanks currently =1100L your average tank size is about 32L/10G , so mostly smallish tanks. If I were you, I'd skip the central concept completely. I'd maintain the sponge use on the small tanks you keep/add and I would use individual cans/hobs on the larger tanks you add.
While not as efficient as a central system, isolating larger tanks w/filters will help avoid a systemic crash if something unexpected were to happen.


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## Narwhal72 (Sep 26, 2006)

I use a mix of centralized systems and individual tanks in my house. I find it works out best for different situations. When I am growing out young fish I used the centralized systems (I have 2 in different rooms). This maintains a more stable water quality and the larger tanks I use in these systems provide more room for growout. When I am working with a pair or breeding group I move them to individual tanks where I can better manipulate the water quality and lighting. 
I would suggest the following:
1. You will need to have all the tanks drilled to accomodate an overflow style drain. A Calfo style overflow works well and occupies the least amount of space in the tank. From these drains you can drain into a sump or wet/dry filter and then through your pump and back to the tanks.
2. use a UV sterilizer on your return line to reduce or eliminate the spread of harmful pathogens in the system. This will keep your fish healthy.

While centralized systems are labor savors they are not energy savers. It costs a lot more to run a large water pump and UV than to run a large air pump.

Andy


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## MoggaDogga (Jul 29, 2008)

Thanks for your replies.

I think I would leave the current 35 tanks on sponges, as these would need drilling plus it would be a pain to route new pipework / drainage. I can also use these for quarantine.

However the new tanks will be large, and can be bought pre-drilled. I've got a some growing Oscars (2 pairs) which given their potential adult size I thought would do better on a central system along with any other new tanks that I add.

With all this in mind the central system would be 2000L max (about 530 US gallons), what size sump tank would I need and what size pump?


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## Narwhal72 (Sep 26, 2006)

That's hard to tell. the sump will need to be large enough to accomodate all the water that drains down when the power goes out. Depending on the volume of your drain pipes that can be quite a bit. I use a the equivalent of a 50 gallon tank on my 350 gallon system. I would probably use a 75 gallon or larger for your system. The larger you go the longer it can go before you need to top off for evaporation too.

For a pump you should get as large a pump as you can afford. The more tanks you have and the longer your pvc runs are the more flow you will need. I am running about 1500 gph actual through my system. My system uses two pumps, a Mag drive 2400 and a Turbo Sea 540. The latter only services one tank in the system.

Andy


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## Narwhal72 (Sep 26, 2006)

That's hard to tell. the sump will need to be large enough to accomodate all the water that drains down when the power goes out. Depending on the volume of your drain pipes that can be quite a bit. I use a the equivalent of a 50 gallon tank on my 350 gallon system. I would probably use a 75 gallon or larger for your system. The larger you go the longer it can go before you need to top off for evaporation too.

For a pump you should get as large a pump as you can afford. The more tanks you have and the longer your pvc runs are the more flow you will need. I am running about 1500 gph actual through my system. My system uses two pumps, a Mag drive 2400 and a Turbo Sea 540. The latter only services one tank in the system.

Andy


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## MoggaDogga (Jul 29, 2008)

When using a sump is it a case of "the bigger the better"?

I've been talking to a local tank manufacturer who have recommended a 6ftx2ftx2ft sump tank to filter upto 3000L. This works out at about 150 US gallons for the sump tank. According to Narwhal72's proportions above, this would be more than adequate to filter 2000L, plus it fits nicely under the 6ft Oscar tank that I'm also buying.


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## Narwhal72 (Sep 26, 2006)

That's actually closer to 180 gallons (U.S.) but your right. Bigger is better. The more volume you have the more stable your water chemistry will be, you can go longer before topping off for evaporation, and you can hold more system water during a power outage.

Andy


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## MoggaDogga (Jul 29, 2008)

Is there rough guide to follow when buying a sump pump? how many times should I turn over total system volume per hour?


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## dogofwar (Apr 5, 2004)

If tanks aren't drilled it's really hard to have a central filtration system.

An alternative would be to build PVC overflows and a drip auto-water change system. This is will allow you to change water as frequently as you want.

If your new tanks are drilled, I'd go with groups of tanks on a single central system. For example, one big tank and a series of smaller ones sharing the same system. I've had good luck with 100, 150, and 300g Rubbermaid feeding troughs as big sumps. They even have a drain at the bottom.

Even with central filtration, I'd keep air-driven filters in each tank. I like a sponge and a box filter per tank. And just a little sand/gravel to make cleaning easy.


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## Narwhal72 (Sep 26, 2006)

your tank turnover rate (each tank) is calculated by T=9.2 (g/f). Where T = the number of hours it takes to turnover 99.99% of the tank volume one time, g= the volume of the tank, and f= the flowrate going into the tank. I try to shoot for 1-2 exchanges per hour. However for smaller volumes it's better to have more exchanges and for larger fewer is acceptable.

this calculation is used when figuring out turnover rate when you are mixing filtered and unfiltered water in the same aquaria.
Andy


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