# Overflow vs canister



## swcurtis (Jun 8, 2009)

I am going to be buying a new tank sometime soon and was wondering peoples take on filtration methods, specifically overflow or canister. Since I am buying a larger tank, and a pre-drilled overflow makes it considerably more expensive, I want to get this right.
Currently I have a 29g with a constant siphon overflow box that drains into a sump and have been using that for about 6 months. I found that there would always be a good layer of detritus on the substrate and plants every week before my water change. I tried moving the return spout to direct water down or at an angle to stir up the water but it never seemed to do much. Last week I sold my turtles and took the Magnum 350 canister filter that they were using, put in the water polisher, and turned it on immediately after a water change/cleaning(when all of the detritus is stirred up) and I found that it really did its job of removing particulate matter from the water making it much clearer. I have only had it running for a week but the amount of stuff that collects at the bottom of the tank and on the plants has decreased either from the new filter, or from the water movement caused by the new filter(the return water flow is much higher than that of the sump), or from both.
How does everyone feel about filtration, sump or canister, what do you use? I like the convenience and bio-filtration of sumps but canisters really work better for pulling stuff off the bottom (which in a planted tank is really helpful). Should I use one, or both?


----------



## LRoberts (May 26, 2009)

I just did a small little post on it. Thought you might want to read it.

http://www.plantedtank.net/forums/general-planted-tank-discussion/89279-how-make-sump-work.html


----------



## wkndracer (Mar 14, 2009)

Sumps if you have room are WAY easier and less expensive to maintain than canisters.
Information is hard to locate via the web though. I converted a trickle filter for planted tank use and received alot of good feedback from the membership here. Also I located active links to George Booths information on the subject regarding CO2.

http://www.plantedtank.net/forums/eq...e-filters.html


----------



## Wasserpest (Jun 12, 2003)

wkndracer said:


> Sumps if you have room are WAY easier and less expensive to maintain than canisters.


Are you sure about this? Compared to canisters, you need WAY stronger pumps to push the water up to the tank. I always thought that made it more expensive in the long run.


----------



## wkndracer (Mar 14, 2009)

Wasserpest said:


> Are you sure about this? Compared to canisters, you need WAY stronger pumps to push the water up to the tank. I always thought that made it more expensive in the long run.


Just built a system and went medium to high end $$$ on all parts, yes I'm sure.


----------



## rbarn (Mar 21, 2009)

Wasserpest said:


> Are you sure about this? Compared to canisters, you need WAY stronger pumps to push the water up to the tank. I always thought that made it more expensive in the long run.


I built this 30+ gallon with all plumbing, filter media and pump
for little over $200 ..... or same cost as large canister filter.

$100 in acrylic from Lowes
$60 in bulkheads and bio-bale and filter floss
$75 Mag 7 pump

Flows 400gph at the tank and has filter media equal to 3 large
canister filters, plus place to hide heaters and evaporation reservoir.

*Flow level of an FX-5 with twice the filter media for half the cost ..........*


----------



## kid creole (Dec 25, 2008)

rbarn said:


> I built this 30+ gallon with all plumbing, filter media and pump
> for little over $200 ..... or same cost as large canister filter.
> 
> $100 in acrylic from Lowes
> ...


The biological filtration of that sump is probably more like 2 or 3 large canister filters.


----------



## rbarn (Mar 21, 2009)

kid creole said:


> The biological filtration of that sump is probably more like 2 or 3 large canister filters.


It's 8.5 gallons of bio-media.

Avg. canister filter probably has 1 gallon or less ................


----------



## Wasserpest (Jun 12, 2003)

Good points, and nice build rbarn. I wasn't comparing the initial cost, but the "less expensive to maintain" comment from earlier. I figured you need about twice the wattage to get similar flow. I could be mistaken though. 

I just bought a Unimax filter that has a volume of between 4 and 5 gallons. Kinda heavy when full. :icon_conf


----------



## gtriever (Mar 12, 2009)

I'm a "sump guy" as well. I like the performance and ease of maintenance, plus the advantage of hiding the equipment and having a clean display tank. Personally, I run a Mag12 (110 watts) with a 40g sump. To achieve the same filtration/flow, I'd probably need 2 FX5s (at 48 watts each), so the difference in cost of operation is so close as to be a non-factor. 


I do want to toss this question into the mix, though: For you sump users, how the heck do you keep the small fish out of the sump? My otos seem to like overflow-surfing; I find one or two in the sump every few days.


----------



## ingg (Jan 18, 2007)

Errr, 1 gallon of media?

I use an Eheim 2260 hooked to my overflow for filtration, which is essentially a 5 gallon bucket full of media. Granted, above has more, but do you need it? I don't need it for a 180g tank....

BTW - it is a planted tank, not a coral tank - you should very easily be able to hide all equipment inside the bulkhead itself. I know, because, well, it is very easy for me....

Oh, and it costs a fraction of the electricity to run vs. actual head pump required of a sump, didn't take me oodles of hours to build, _and doesn't offgas CO2_.  

The only way I know of to avoid offgas in a sump style is to modify it heavily to make it enclosed - which negates the whole "open and easy access" thing folks rave about anyhow - and turns it into (essentially) a very expensive to run and not so fun to clean canister filter. I would be interested in learning about other ways to avoid the offgas, though!


----------



## snafu (Oct 9, 2004)

why does a sump have to offgas CO2 a much as any other method? if the water is cascading over some media run in a wet/dry type of arrangement, i could see that being a problem. but using a sump doesn't have to necessarily equate to significantly more CO2 loss.


----------



## Regloh (Jan 17, 2009)

Ok, maybe that whole outgassing issue has been discussed elsewhere, or maybe it's worth a separate thread, but wouldn't it be as simple as putting a loosely fitting lid on the sump?
CO2 is heavier than air and if it outgases it blankets the sump only to re-disolve. I don't know, you hear so many people saying that you can make sumps and CO2 work, that it really shouldn't be such a big argument. 
Well I'm a canister guy too, but sumps intrigue me, especially since that old tank that most of us have kicking around in the garage would be so easily converted 

EDIT: Hehe... got ninja'ed... couldn't agree more


----------



## wkndracer (Mar 14, 2009)

Article and case study regarding CO2 loss by George Booth.
http://aquaticconcepts.thekrib.com/Co2/index.htm#loss
Where’s the issue? 
 I fabricated a two piece glass top that allows me to remove media baskets in a minute without draining or disconnecting anything so no drama there either.
My 75g tank running an Eheim Pro3e requires a power head in tank to supplement flow. The Mag drive will not with its four discharge nozzles. The test run showed on dead spots in circulation.


----------



## plantbrain (Dec 15, 2003)

wkndracer said:


> Article and case study regarding CO2 loss by George Booth.
> http://aquaticconcepts.thekrib.com/Co2/index.htm#loss
> Where’s the issue?
> I fabricated a two piece glass top that allows me to remove media baskets in a minute without draining or disconnecting anything so no drama there either.
> My 75g tank running an Eheim Pro3e requires a power head in tank to supplement flow. The Mag drive will not with its four discharge nozzles. The test run showed on dead spots in circulation.


Steve and myself mirrored George's comments and findings as well independently.

I use both Canisters and sumps.
I think overall and in the long run, the sumps are the way to go.

Seal the wet/dry section lids, vent holes, and raise the over flow so there's 1-2" drop only.

No CO2 loss.

Energy wise, Canisters are a good deal..........but..........

If you add a high flow low pressure wave pomp in the tank, you can use less pump flow for the overflow(and reduced noise from overflow) and the same is true for the canister. Canisters are quiet, harder to clean and leave lime lines from evaporation which I hate.

Trade offs for each.

For tanks under say 55-60 Gallons, canisters are good IME/IMO.
Larger than say 70 Gal, I good with sumps.

You can add cansiters + sumps as well, have a small sump etc for surface skimming, equipment etc, then a canister as well for mechanical or Bio or Chem etc.

Regards, 
Tom Barr


----------



## wkndracer (Mar 14, 2009)

Thanks for weighing in Mr. Tom.
Regarding the final contested point of long term costs. 
(IMO and experience) 
My Eheim’s use a claimed 35watts of power and for the size of my current project I would need two of them. 

Personally trying to cut bulk floss to match the baskets of my Pro3e including the odd shaped pipe ports is a PITA. The factory pads are not cheap or are they sold many places. Also current pricing of the unit is still approx. $349.00 plus shipping.

I have substantially greater flow but will be using a 30watt increase in power. The generic buy anywhere filter materials are much cheaper. The bio ball media section of the filter should never have the bacteria disturbed as it is when every three months the canisters are cleaned so that will be more stable.

I’ve yet to have a seal leak on my 3 running canisters (knock on wood) but have had double tap connector issues. Again expensive (relative) to replace. There’s no perfect bullet for all situations but the bad rap for sumps on the forum is not warranted. (Again IMO)


----------



## plantbrain (Dec 15, 2003)

Save yourself 200$ and get a Rena XP3 etc.
Then a small sump set up.
Ehiems are nice, but not for 350$, I do not like the Fluvals.
Rena is good compromise. 

Then you have the best of both.
should use maybe 30-40 Watts with a smalle rRainbow return pump and then the rena is about 30w.

60-70 Watts for say 600-700gph of very well filtered water that can be directed in many ways.

Then if you want more, add a small low pressure high flow for 10-18w for 1200-2000 gph of mixing.

Regards, 
Tom Barr


----------



## ingg (Jan 18, 2007)

plantbrain said:


> Seal the wet/dry section lids, vent holes, and raise the over flow so there's 1-2" drop only.
> 
> No CO2 loss.
> 
> ...


Thank you for saying exactly my point.

Once you seal it, it is a bulky, see-through, power hog of a canister filter - that is the flat out truth of it in ym little world. 

I really do want to try and understand the advantage of a heavily modified sump application, but just can't see it. (For the record, all the "hide the equipment", "dump ferts easier", "easier to clean", blah blah blah go right out the window as soon as you seal that unit in my eyes. And often even before, as overflows themselves can be used for most of the 'advantages' often talked about.  )


On a side note, I do have to say that since my tank is plumbed to my house and auto-topoffs, I don't have to deal with any lime lines or evaporation. I do guess for some that might be one reason for my thinking on my 180g - it does need more attention to evaporation than my other tanks given the high level I keep in the overflows (there is zero splash in my overflows). 


I have to look for it, I would swear right here on plantedtank there was a fellow measuring the CO2 loss in his sump vs. his tank and it was astronomical - like a full PH point kind of astronomical IIRC. I'll try and find it. Tom, I'd swear you were trying to help the guy, too, it was some time ago....


----------



## rbarn (Mar 21, 2009)

Personally I dont see what the big deal with Co2 loss is.

Get you a 20lbs tank, kick the bubble rate up and refill
the tank for $15 every 3-4 months.

My 60gal with unsealed 30 gal sump is a Co2 hog.
But who cares, just get a decent sized bottle. co2 refills are dirt cheap.

You're "wasting" $4 a month in Co2 ...... ouch :icon_roll


----------



## wkndracer (Mar 14, 2009)

A Rena xP3 is sitting in the box, reserved in case of replacement need on short notice. The plastic assembly is even cheesier than Eheim and I’m not seeing it as a gain vs cost for the best quality.

Sealing a sump is not a PITA,,, neither is accessing it. Two ¼” glass plates.









A lid is lifted and a basket or two removed for servicing,, _Gee that's hard_. 

Not easy like removing one of my canisters from the cabinet and taking it to the laundry room or outside. Breaking it down, cleaning the mum out of the seal areas, cleaning the impeller, housing, media, refilling, connecting hoses. 

Everybody raises the over flows to eliminate the splash / noise already and its not hard either. 

*The only wrong way to keep fish and weeds is the one that ends up all over the carpet* :icon_eek:

Metal Halide lighting, the computers we're all running to post on the internet are all 'power hogs'. The choice to use a sump on my tank or others has its advantages and cleaning / servicing it is one of them for me.

Two quotes from Mr. Toms earlier posts here as well along with my take on them.
_*
60-70 Watts for say 600-700gph of very well filtered water that can be directed in many ways.*_

30 watts additional for 875gph @ 6'. Also the engineers and PDM group techs where I work state testing repeatedly shows applied head/back pressure on pumps actually reduce the amp draw on the drive motor at an ever increasing rate of amperage drop until just short of dead heading the fluid system. As opposed to running free flow where the motor is at maximum amp draw. Power Group (Electric Generating Industry) tests actually have proven equipment service life improves on motor armatures and windings if the motors are ran loaded to the point to reduce motor RPM below maximum. Without hypot testing my sump after start up I can't say what the power consumption will actually be. If I was that penny wise I would'nt have 5 aquariums anyway.:icon_wink

_*Energy wise, Canisters are a good deal..........but..........

If you add a high flow low pressure wave pomp in the tank, you can use less pump flow for the overflow(and reduced noise from overflow) and the same is true for the canister. Canisters are quiet, harder to clean and leave lime lines from evaporation which I hate.

Trade offs for each.

For tanks under say 55-60 Gallons, canisters are good IME/IMO.
Larger than say 70 Gal, I good with sumps.

*_Every tank I've put together has been different with the exception of the bookend 75g set in the living room. I've enjoyed researching and assembling this one with the sump as much if not more than the others. The information was harder to find. There is value in that to me as well.:biggrin:


----------



## sunfire99 (Apr 8, 2009)

gtriever said:


> I do want to toss this question into the mix, though: For you sump users, how the heck do you keep the small fish out of the sump? My otos seem to like overflow-surfing; I find one or two in the sump every few days.


I had the same issue with Cardinal Tetras surfing. I made a screen from plastic mesh found at the local Walmart craft section. I cut some of the cross pieces out to make a few larger holes, but still nothing that would allow a grown fish to escape through it. I check it periodically for debris, etc but find I don't need to "clean" it at all. 



rbarn said:


> Personally I dont see what the big deal with Co2 loss is.
> 
> Get you a 20lbs tank, kick the bubble rate up and refill
> the tank for $15 every 3-4 months.
> ...


I've had a 5lb cylinder running my 100+ gallon tank with sump and canister filter running for 2 1/2 months so far maintaining 30 ppm all day every day. Done right, sumps don't offgas that much CO2 and you're right, that CO2 is cheap relative to so many other things in this hobby.


----------

