Questions on twin canister flowrate and setup

[tawauboy]

Firstly, IMO I do think that if you do link cannisters in series, you should use the "pull" method. As cannister body are designed to be pulled. As you can see that based on one cannister, the impeller are pulling water from the cannister body out to the output.

the canister inlet should be gravity-assisted and not pulled by the impeller. the impeller helps to 'push' the water back into the tank.

in general, negative pressure (suction pressure) is avoided in the impeller chamber to prevent cavitation. thus, it is good practice to throttle a filter's flowrate by using a valve at the output only.

Furthermore, what you said "the output is connected to the input of the second lower flowrate (preferably equal or slightly lower)." does not make any sense. What's there to be specific about the flowrate when it's a non-powered dummy?

if the practice of throttling at the outlet is followed, then the unpowered canister needs to be placed at the output of the powered filter. a smaller flowrate filter will usually use (though not always) smaller diameter pipes and these will restrict flow.

Cannister are designed so that it can make use of the water pressure from the tank that you are powering itself to generate flowrate. Unlike pumps, most external cannisters uses very little power. Water pressure will direct the water to the same level of the water in the tank itself, then the cannister will furthermore power the flow into the tank that it's servicing on. Whereas a pump, pumps water from I.e the sump to the top tier of the tank. This is pure power, negligible water pressure involved.

[reiner09]

Haha, BFG. I do think that the reason for part B applies to the senatio whereby both canisters are running in series, with both of them turn on. Then there will be a push or drag happening to the impeller part of the second canister. This may cause the motor part of the canister to weaken overtime.

However, if we are talking about one of the canister being off. The impeller in the first place will not even move!
There is forum members stating that if you do not remove the impeller, there will be a bottleneck effect. But I do think that there Would not be any as most, if not all ehiem canisters are designed like this (shown in attached photo, example of a 2211) there should be no area for the bottleneck effect to happen and no way that you ate going to spoil the impeller if the impeller are not going to move in the first place. cheers

yep,agree with the point on the drag causing the motor to weaken over time..

about the impeller part, do you think it will be better to do without the impellers in the dummies? I personally think if the impeller 'flippers' isn't there to obstruct the water flow,maybe...just maybe...the flowrate might just improve...by a little at least?


and yes the canisters do not exactly work like a pump ... whereby the pull and push action that takes place in a normal pump,the is a large degree of siphoning effect aided by some kind of pressure difference and gravity... if it does work like a pump, we won't have so much difficulty priming it ( if you notice sometimes if primed incorrectly,the water in the tubes will go forward and backwards unable to flow throughout the whole piping)..

and also i usually adjust the throttle at the outlet only following the advises in some other thread..and now i know the reason..thanks mod tawau..

[rubbersandal]

Thks zack.

nope. it does not work in the way you'll like it to. the 'cleaner' water coming out from the 'mechanical filter' will mix with the 'dirtier' tank water and goes into the 'biological filter'. very soon your 'biological filter' will be clogged. there is a purpose in the arrangement of different filter media types in a filter and BFG has explained this earlier.

if you want to run 2 filters in a tank, you either run them as individual filters (each with its own complete set of filter medai) or in series (explained by BFG). the output of the individual filters can be placed side-by-side or at opposite corners of the tank.

if you want to run 2 filter in series, the first filter is the one with higher flow rate and is the mechanical filter. the output is connected to the input of the second lower flowrate (preferably equal or slightly lower). this second filter is the biological filter, is unpowered and the impeller is removed. the is minimal impact on lifespan of the filter as the filter output is designed 'to push' water up a certain height. this will be similar to the 'resistance' caused by the second filter.

Thanks zack



Ok so fr wat I understand if I opt for 2 or twin canisters running individually.
With full set of media that is hving both mech and biological media in each canister, having 2 inputs side by side on one side and having outputs side by side on opp direction?
Still this connection does not mean A+B flowrate rite?

[ZackZhou]

Yes. You can do that.
But with the question to whether your flowrate is = to A+B, in what sense ate you talking about? If you want to compared with the online recommended flowrate in terms of ?xthe tank volume, yes I may be considered as A+B.
Example: you tank volume itself is 50L, with 2 cannisters effective flowrate as 400L/hour, you will be having a good flowrate of 16x the rank volume.

Besides the above usage of term flowrate, alot of people usually need to find out flowrate when they are running a chiller, as chillers need a minimum flowrate to operate effitively. In this case, the flowrate does not equals to A+B.

Sometimes in fish keeping, you need to be like doing math, everything also need to measure. As long as your ways work, continue to use it.
Cheers

[BFG]

Thks zack.




Thanks zack



Ok so fr wat I understand if I opt for 2 or twin canisters running individually.
With full set of media that is hving both mech and biological media in each canister, having 2 inputs side by side on one side and having outputs side by side on opp direction?
Still this connection does not mean A+B flowrate rite?

Yes, it does not mean a A+B flowrate. The flowrate in the tank would be of the higher flowrate canister filter but not necessary true due to obstruction in the tank itself.


On another note, please do not use sms language in this forum. Hate to see this thread disappear due to the topic starter not adhering to forum rules.

[tawauboy]

what's the reason for the emphasis on A+B?
care to share?

[rubbersandal]

what's the reason for the emphasis on A+B?
care to share?

Thinking of having 2 canisters which I'm able to do maintanence or when one need servicing the other is still running. An ideal flowrate is 2400 l/h I'm after.

[ZackZhou]

what's the reason for the emphasis on A+B?
care to share?

That's the question that I wanted to ask as well. Haha

[eviltrain]

If you wants to get 2400lph flowrate, you can never achieve from a+b.

For example, both a and b is 1200lph each. Both are link in series and on "on", they are not equal to the 2400lph you wants. They are still only 1200lph no matter what. What you have more is more different type of bb cultivated.

The closest you can get is A as one filtration system and B as another filtration system.

All these still boils down on what you wants to achieve from the setup.



Send from my GT-P1000 (Overcome 7 Series v4.0.0)

[rubbersandal]

I see thanks.
Aiya sian whether have 2 canisters running in series or separately they still cannot give me my ideal flowrate of 2400 l/h.
I guess the only way is to get one single eheim 2260 sian.

[tawauboy]

Thinking of having 2 canisters which I'm able to do maintanence or when one need servicing the other is still running. An ideal flowrate is 2400 l/h I'm after.

any concerns with servicing both filters simultaneously? or any issue with your tank being filter-less for a short period of time.

what is your tank size that requires you to achieve 2400l/h?

even if you get 2260, which is rated approximately 2400l/h, you will not be able to achieve 2400l/h on long term. 2400l/h is the figure that you'll get when it is new. once the filter media start clogging up and the flowrate will go down.

[rubbersandal]

any concerns with servicing both filters simultaneously? or any issue with your tank being filter-less for a short period of time.

what is your tank size that requires you to achieve 2400l/h?

even if you get 2260, which is rated approximately 2400l/h, you will not be able to achieve 2400l/h on long term. 2400l/h is the figure that you'll get when it is new. once the filter media start clogging up and the flowrate will go down.

I know the flowrate wont be 2400 l/h even if I get myself 2260 due to media etc.
Having a 3ft tank planning to keep altum or discus though the season had jus ended, but am preparing ahead and gather info on setup for the next season
Getting 2400 l/h is hopefuly I can get (a guideline for me), and also that 2400l/h just laying an example to the question of this thread whether a parallel setup of 2 canisters running would that mean A+B or 1200 l/h +12100 l/h flowrate thats all, not a die die must have flowrate as you thought i'm insisted.

What's more important is if one canister is down need to service there's still another one running and also just my preference to have one canister clean up at a time.
Apologise if my reply is somehow huh to you.

[tawauboy]

servicing as in regular cleaning of filter and changing the wool pad? i doubt that there is any side effects if both filters are stopped for servicing. if you still worry, get a power head to keep the water circulating.

based on you preference, you should be looking at 2x 2028 and not a single 2260.

[Shadow]

....... thread whether a parallel setup of 2 canisters running would that mean A+B or 1200 l/h +12100 l/h flowrate thats all, not a die die must have flowrate as you thought i'm insisted.

If what you mean by parallel is 2 input and 2 output, that should be do able.

[rubbersandal]

Thanks tawauboy and shadow clearing my mind and yr patience here.