filtration for new 75 gal?

[bayw]

I am setting up a new 75 gal. freshwater aquarium for fancy goldfish (probably 4-5 total, starting small: 3" each). I have 3 questions:

1.I am thinking of using the Eheim 2026 canister filter. Will this be large enough? I know it is rated for 92 gals. but I have read that you should use twice as much filtration as the manufacturers recommend. Is this true with Eheims too? Would the 2028 be overkill?

2.I will also use an undergravel filter. The useable interior footprint of my tank is 46"x16". Will either Perfect-a-flo 48"x18" (for 75 gal) or the 48"x13"(55 gal.) fit my tank? I am assuming the 2 powerheads recommended are needed one each for the two plates. Do these pull water down through the gravel or push it upward through the gravel? Would airstones also be needed if I use the undergravel filter?

3. I am also thinking of using a UV sterilizer but I am unclear as to how to size this correctly with the above filter set-up. If the UV is arranged in series with the filter outflow the flow rate would be too fast to be effective. If the UV is arranged on a bypass loop then how do I know the exact flow rate in each of the 2 "branches"?

Any information would be appreciated as I am anxious to order and finish setting up my tank. Am I overlooking anything?

[AquariumPro]

Hello and welcome!

The 2026 would be fine.

That is the correct undergravel for your tank. We have the outside dimensions listed for the tanks the filters fit, as most folks don't know to look at the inside dimensions. Those plates will fit fine.

Yes, the undergravel will require two powerheads, as you should always use one per two linear feet, even if the plate was one-piece. Go with smaller models, as fancy goldfish do not like hard current. I would use Hagen 301 PH.

Not sure a UV sterilizer is a good investment for a freshwater goldfish tank. Waste of money in my opinion and I own the web site! It's so easy to change water in freshwater that using a UV sterilizer is rarely done, except if you are keeping sensitive fish such as Discus.

For goldfish, buying healthy specimens and then not making the mistake of feeding the same diet all the time (the number one mistake by goldfish owners) will usually result in beautiful disease-free specimens. The only external parasite that Goldfish get which is difficult to cure is anchorworm ( a parasitic crustacean), and uv sterilizers will not kill the larvae unless you have a very large (25 watt) model. You can avoid anchorworm by simply carefully examining any fish you buy for red sores or raised scales. Also, don't get snails.

[bayw]

Thanks so much for your prompt reply. I will place my order now. I am very excited!