To Canister filter or not to canister filter

[newbie]

Hi Everybody,

Lately i've been doing a lot of research prior to purchasing anything for my Discus display tank....i've decided on the dimensions for the tank (6ft long X 2ft wide X 2.5ft high) and am getting prices for constructing that...in the meantime i'm also looking at filtration. I always thought canisters were the way to go but a guy mentioned to me today that for Discus canisters arent the best option. His reason fell back to the bacterial basis through which the canister filter worked saying that the Discus don't like a high bacterial load in their water. Is this correct? If so what is the best option for filtration?

Thanks

D[/i]

[Benny]

high bacterial load in their water?????

That doesnt make sense... Theres little bacteria in the water.... The bacteria colonizes on filter media... Doesnt float around much comparitively...

For a tank of that massive size you would need several HUGE canisters.. its approx 850L tank, so you need to cycle that at least 4 times per hour, thats a 3400 liter per hour canister (none exist that large)....

In my opinion a wet dry filter underneth the tank (sump filter) is practically the only way you can effectively filter a tank that large!!!

I think what your friend was trying to say was discus will impose a substantial bio-load on a filter, and it needs plenty of media volume to compensate for it (MORE bacteria leads to more effective removal of highly toxic ammonia and nitrite)

I would be looking at a 3 foot sump, if not 4 for a tank that big!!!

Regards,
Benny

[newbie]

Hey Benny,

Thanks for your reply.....this guy was from a LFS and it was a "from my experience" comment....i thought he was a bit nuts :roll: when he told me but hey who am i to judge :D

I was planning on running a canister filter along with a DIY sump style bio-ball filter underneath the tank. I was planning on making it 4ft long X 2ft wide X 1ft hight and divide it in to equal sections. Each section would be open ended and the sections would be filled with bioballs...the open ended sections would encourage the water to move in a continual 's' style in the filter to increase the contact time/efficiency with the bioballs (hope all that makes sense)

[Proteus]

In regards to your tank dimensions, IMO it would be better and easier to maintain if it were 2.5ft wide, and only 2ft deep. (plus with more surface area, a better oxygen exchange level is maintained)

Trust me on this, 2.5ft deep, unless really necessary can prove to be a headache especially for substrate/surface cleaning (you will get wet)

[kalebjarrod]

i would not try to canister filter a tank that big

just get a decent sump going, and if you do proceed with it being 2.5ft deep this will give you a better gas exchange

you can but some pretty great sumps for a preety cheap price these days that would more than handle the load (this is on a pic of a 400lt variety you need the model a few up LOL)

[newbie]

kalebjarrod, that's one nice sump! where does that come from?

Proteus, i definitely see your point! food for thought....the original reason i thought 2.5ft high is i figured the extra depth would be good for the Discus give them a bit more vertical room to roam in...the 2ft wide i figured coz i don't want the little critters hiding at the back of the aquarium.

thanks again for the advice, much appreciated

[kalebjarrod]

Pretty standard unit available from most LFS :wink:

[newbie]

kalebjarrod, or anybody else that knows, would those bioballs be immersed in water? it appears the bioballs are in their own 'compartment' would the base of that simply have holes in it for the water to trickle out? i'm guessing that the water simply trickles between the bioballs from the spray arms and that they are not permanently immersed to increase the available oxygen to the bacteria. Also, i'm guessing the spray arms would be gravity fed and that the return pump would sit in the other end of the sump. The tank needs to cycle through about 4 times an hour doesnt it so that means for my tank (of approximately 810litres) i would need a pump capable of running at about 3200l p/h. Is there a certain amount of bioballs that there should be per litre of water for efficiency? the larger of those reef surge sumps has 840 bioballs and that is rated up to 900litres. I can feel a sudden urge of DIY...does anybody know a rough price for acrylic sheet? what could one expect to pay for bioballs? and does anybody know where you can source the rotating arm fittings?

[kalebjarrod]

the roungh rule is one (1) bio ball per lt

and as for pumps you would need a pump that could do around 4500lt per hour once you take into consideration "Head" and friction

the bioballs in the above sump sit just level with the water, but they can sit up to 1/3 submerged

the blue bi balls and slighty boyant so you can't submerge them any more than this

[newbie]

So that top compartment does fill with water? and then trickle out....so you would need to ensure that the amount of water flowing out is equal or more than that flowing in. Do the bioballs need to be immersed to function? good point about the pump flow...thanks

[kalebjarrod]

Bio balls don't need to be immersed to function

the top compartment does Not fill with water, unless you overfill the whole unit :wink:

it has more than enough holes to allow all the flow the unit can handle

[newbie]

cool, thanks kalebjarrod, so the top compartment has the water trickling over the bioballs without them being fully immersed...cool....off to the drawing board :D

[newbie]

Had a bit of a play today and came up with a design for a sump.....similar in design to the Reef Surge....800 X 320 X 500 with two chambers for bio-balls each measuring 300 X 300 X 400. The sump has a weir with the volumes being:

Sump full - 128 litres
Sump operating - 77 litres
Bio-ball chambers - 72 litres in total

The chambers sit in the main sump just above the water level which is maintained by the weir.

Does anybody know roughly how many bio-balls there are per litre of filter space (i know this depends on bio-ball size but just a rough idea would be great) and how many bio-balls should one have per litre of tank?

I priced up how much it would cost me to do it in acrylic and one price i have gotten so far is $280 for the acrylic alone.....ouch