Right GPH and Filter options for fancy Goldfish

Hi all, great forum, i found lots of question already answered and learned sooo much!
I’m planning about an aquarium with 1 to 3 fancy goldfish.


I read that I’ve to count 20 gallons for the first goldfish, and other 10 for each additional goldfish. I also read that I’ll need to filter the whole tank x10 times each hour. Finally, I read about the “never too much filtration” versus “you can have too much current” guidelines.


All that means:


1 fancy goldfish - 40 gallons - 400 GPH filter
2 fancy goldfish - 60 gallons - 600 GPH filter
3 fancy goldfish - 80 gallons - 800 GPH filter


My Problem is that, whichever one I’ll choose, I can’t put the aquarium in its own stand, but I’ll have to choose some existing (sturdy) furniture (small apartment).


That means that, if I choose a canister filter, it will be placed on the same surface, on the side of the tank. I read that one can do that as long as it’s under the water level. That can be a problem, as the biggest GPH are quite big (I’ve looked at eheim classic in first place) and they can reach the height of the tank (the plastic pipes should make an “S” from the end of the Lily Pipe up to the canister)


On the other hand, if I ‘surrend’ to an hang on filters (like, for example, the Hagen Aquaclear) I’ll have not ‘placement’ problems, but I’ll be unable to use Lily Pipes that, in the case of the “spiral/spin” model or the “round cup” model, can considerably reduce the output flow (I’ve also seen some ideas to reduce flow in Aquaclear models, but to me they appear very unaesthetic, plus I’m not a big fan of DIY). On top of that, I got this idea that canister are better, and I dunno if an hang on filter while having the right GPH, can do the "goldfish job”.


QUESTIONS:


1) are my premises correct?
2) can I lower the GPH?
3) can I have the canister on the side with “S” piping?
4) or can hang on filters do well “the goldfish job”?
5) will the current from hang on filter of correct GPH will be too much?




Thank you for your attention till here, and for the time for your answer if you please! - a very excited Aquarist Wannabe

First of all, in an attempt of thinking in gallons (I think in liters) i did a mistake of conversion.
Correct values are 20g(200GPH) +10g(300GPH) +10g(400GPH).


@ FreshyFresh Thank you!
So you find there's no problem at all whit hang on back like aquaclear, I'll keep the info in mind

@ RBishop thank you! I think i figured this out.

Ok, lot of self research and a bit of compromise with reality and space issues.

This will be the setup:

2 fancy goldfish

ADA 'bare' glass tank
60 x 45 x 45 cm (about 24 x 18 x 18 inches)
121,5 liters (about 32 gallons)

Eheim classic canister filter
model 600 id 2217
x 1000 liters per hour (about 264 GPH)
Height 40 cm (about 16 inches)
Diameter 20,5 cm (about 8 inches)

Thank all.

@dudley best I can do is 12-13 inches below, I'll try.

I can't deny I am bit puzzled by the topic.
Everywhere I read that canister do use gravity to work - the more the better... BUT
True is that there is a stated maximum height for the impeller to push water back in AND
The minimum value of gravity required is nowhere to be found.
So I ask myself if the force not utilized to push water back in the tank could be utilized to suck water in the canister (in a certain max amount).

For example, eheim do make a specific canister for side positioning (the aquacompact), but I think the power source is displaced outside the canister, in the tank.

Another question could be if pipes from canister to tank can go horizontally, allowing to put the tank (13 inch up, but) at the far end of a long forniture.

@ Sploke Thank you! It was my conclusion but there is a bit of confusion around that topic as not everybody agrees. The first question was about the opportunity of an Hang on Back filter, but that was solved settling with fewer GPH (about 264 GPH for an about 32 G tank), due to the smaller diameter of the canister.