Sumps Vs External Filter

[dgwebster]

Ok, I have my 47 gall tank - its nice

im now thinking about the purchase of a filter for it.

I have been settled on an Eheim Pro 2224 for a while now but at nearly £100 including media, its a little expensive. I think anyway. but thats about its only draw back - ismple to maintain, control and implement. and small.

But im also thinking about a Sump - one because i *think* i can get it for cheaper along with the following bonuses:

1) can remove all equipment - heater etc and put into the sump
2) the tank already has sump holes cut out
3) it creates a larger water volume overall = healthier fish environment
4) easier water changes etc.

it does also have its drawbacks though. But they are something else.

My questions on sumps are numerous. Can anyone help with these:

I can get a 30x15x15 sump for £15 - would this suffice for the 47 gallon tank?
Water size of pump would I need to pump the water back up into the tank?
Can I purchase an overflow thingy ready made, if so any suggestions? You know, one of those things that will stop wate flow if the pump fails...

 

[RipSlider]

The thing to remember is that a sump itself provides no filtration whatso ever. You'd still need your external filter, it would just be placed in the sump. Also, becuase you are increasing the water volume, you may need a bigger filter to deal with it.


Sumps are good for the reasons that you discuss above, but there are negatives as well:

Needs more filtration that a sumpless setup
it's noisy - not the best for a community living room
You'll need weirs or durso pipes added to the main tank
there's a lot more plumbing involved
theres a lot more reliance on the return pump ALWAYS working.

With a 47 gallon setup, assuming that you just want to keep general community fish, I see the last point as the major issue.

The return pump will needs to balance the external filter you add to the sump - you want the pump moving roughly the same amount of water so that you are constantly filtering dirty water. If you dso this with the size of sump suggested, you may well be adding too much flow for a lot of community fish to be happy.

With a 47 gallon tank, persoanlly I would stick to just having the external filter. Otherwise, you'll STILL have to get the filter, but you'll be paying extra for the sump, the return pumps, the weirs, and you may even bring in extra costs such as needing bigger heaters as you have more volume.

Steve

 

[dgwebster]

ok i thought the point of a sump was to also be able to fill chambers with filter material, hence no need for a filter as the sump is a filter...

I will also be completely honest, the sheer size required is another consderation - the eheim 2224 is ALOT smaller

 

[CFC]

The thing to remember is that a sump itself provides no filtration whatso ever. You'd still need your external filter, it would just be placed in the sump. Also, becuase you are increasing the water volume, you may need a bigger filter to deal with it.

Where on earth does that idea come from?

The whole point of a sump is to replace conventional filters when the main tank is too large to realisticly filter with standard canisters and volume of media replaces turn over of water.

For instance the optimal flow rate for a standard filtration system is 5x tank volume per hour, for tanks up to 150 gallons this is easily acheivable with a couple of large canister filters both pumping 300-400g per hour through the media. With larger tanks things become a bit more difficult, pumping thousands of gallons of water requires huge pumps which just arent fitted to conventional filters, the largest Eheim filter available only has an output of 634 US gallons per hour and has a power consumption of 65 watts so running two of these would add a substancial ammount to the electricity bill.
The answer is to use a sump with multiple chambers filled with high surface area filter media through which the water flows, the sump should have volume of at least 10% of the main tank and allows a slower flow rate through the media as there is more water in contact with the media at any one time than there is in a conventional canister filter.

For tanks under 120 gallons there is very little point in using sump filtration unless you really want to.

 

[dgwebster]

i think thats been the single most valuable bit of information on sumps i have ever read.

 

[andywg]

It all depends on the aims and goals. Sumps allow greater flexibility through larger water volume and increased capability to hold media (also you can throw a wet dry on which, in my opinion, is one of the best things you can have for freshwater.

However, sumps will make doing a planted tank a lot more difficult due to the fact the operation of a sump tends to gas out all the CO2 you would need to be pumping in.

Also, sumps tend to be more expensive once you have factored in buying the pipework, the second tank, and (most importantly) the return pump.

As CFC says, under 120 gallons you don't need a sump. I however like them and have got one on all of my tanks now except my shrimp breeder tank, but one of the main reasons for this is the ability to run two tanks off of a single filter.

I must say that ripslider's post is the most wildly inaccurate post on sumps, and possibly this entire forum, I have ever had the misfortune to read. I don't say that for way of flaming, but to point out that he has got the entire thing wrong and his advice should be discarded.

 

[dgwebster]

i thought as much.

Your comment on being ableto filter two tanks etc is another common reason behind my question: im thinking about adding to the 4ft tank two 2ft species tanks (dwarf puffers and another small agressive) and was wondering about the factor of being able to bring them all under the same filtration.

[edit] but that is also asking for trouble - if one fails, all tanks are in danger - with seperate filtration, all may not be lost unless its a power issue.

 

[andywg]

I currently run a 3x2x2 and a 48x15x18 off of the same wet dry tower and sump.

You do have the cross contamination issue, but if you look after the fish well, you shouldn't have too much trouble anyway.

All I did was have the drains meet in a t junction shortly before they run out on to the filter floss above the wet dry.

Here is a pic of the joining of the drains:

And here is the system setup, you can make out the tower tot he right of the 3 foot tank.

HTH

Andy

 

[Teelie]

I like sumps and I'm definitely going to use them on larger tanks when I set those up, but as CFC said, anything under 120 is really just personal preference and not a real advantage to an external filter of some sort. I have gone from HOB filters (on my 10 and 30's) to cannister (on my 55) and I personally like how much less noise the cannister makes (none), and it's out of sight inside the stand. All you may see are two tubes in the back where water comes in and goes out. Pretty much the same effect as a sump but cheaper.

Of course if you want to run two tanks on one filter, a sump is the way to go but it does guarantee if one tank fails, the other is likely to get whatever happens too. And you'll need fish that prefer the same water parameters.

I used to work at an LFS and let me tell you, sumps can be extremely noisy and tempermental if something goes wrong. I'd say go with an external filter for your needs.