I have a 20 gallon tank right now with 1 Ryukin and 1 Fantail. I am picking up a 55 gallon this weekend and was wondering how much filtration I will need. I plan on keeping 5 goldies in it. Right now on the 20 gallon I have 2 Aqua Clear 20's and a Whisper 10. That is about 300GPH as of now. I was thinking of getting a Eheim 2213 canister filter that Big Al's claims can handle up to 65 gallons but it only does 116GPH. Instead of that though I could get an Aqua Clear 70 that does 300GPH for almost $20 cheaper. What do you all reccomend? I was thinking of even making my own canister filter.

welcome to kokos. if you have questions, this is the place to find answers. first, you want to have at least 10x the amout of filtration for the gal size of your tank. so if you are getting a 55 then you will need at least 550 gph turn over. that is the general rule of thumb around here. depending on the size of your fish, you are gonna need more turn over along with more water changes. as for the questions on the filters, you can do a combo of all 4 hang on back filters since the canister and the 3 that you already have will not meet the demands. as for a diy canister, check out the "diy" section of the board as there is one in progress and you can get some ideas for what you are gonna need there. i can really get into depth with you on this topic but this is just a quick generalization. the more you read around here the more you will learn. its a lot to take in so take your time and fire away with any questions that you might have. there are plenty of people around that are more than willing to help you out. in one way or another, we all are here for info. have fun and good luck

Are your five goldies going to be fancy goldies? If so, that is just fine but if you are wanting to keep single tailed goldfish then that is overstocked. Fancy goldies usually need 10 gallons each, while the regular goldies require at least 20 apiece.

I prefer to have a canister filter on any tank as big as or larger than 20 gallons. Canister filters give your good biobugs a really good place to call home, and actually require very little maintenance. I use a Eheim Pro II canister on my 29 gallon, with an emperor 400 on the back as well to get the filtration that I need.

I have my canister set up with a spraybar for the water return, that way I get more surface agitation to keep the water well oxygenated and it helps keep it a little cooler now that we are entering those wretched summer months where the tanks heat up.

Are the Penn Plax Cascade canisters any good?

I don't know if you know this but the Penguin 350 filters 350 gph and it is only $26.99 on the P. Smart website, compared to the Aqua Clear 70 which is $ 41.29 and filters less. I have one and it works really well and has 2 bio wheels.

You make a good point but, I don't think the Bio-Wheels have nearly as much mechanical filtration as the Aqua Clears.

Ok, I just thought I'd mention it.