hiya
I want to upgrade my filtration system for my tank I have a 30 ga tank I was wondering what would be the best filtration unit to get that is going to be worth purchasing and what gph would suit it i have to filter systems on my tank 1 single and a biofilter double cartridge

Avoid undergravel filters they are not much good for goldfish.In my 30 gallon I have a Fluval 3plus and a Fluval 2plus.

Heres link on filtration you may like to read

http://www.kokosgoldfish.com/Filtration.html

i have a aquaclear 70 + fluval 104 canister filter for my 30 gal tank totalling 440gph. the minimum rate for your tank is going to be 300gph. the HOB is good for filtering out the large chunks while the canister i jam packed it with biomax for maximum biofiltration.

hiya thanxs for the suggestions i'm just going to look on the web for one hopefully i find a descent one

Any particular reason for that? We're looking at a 30gal with exactly that kind of filter.

Cheers

Goldfish produce far too much solid waste for an Undergravel Filter to handle, also the turnover rate is not usually enough because it is powerd by an air pump. They can be horrendous to maintain and keep clean as well, they also trap harmful gases that build up. They can work with very small fish, but generally speaking the bigger the tank and fish, the more useless they are

Jillian - I agree with disaster999, add an appropriatly sized cannister filter together/in combination with what you already have and that will work great. Alternatively get a large cannister filter for the whole tank, although having a secondary filter is a good idea anyway. I have a cannister filter and I think they are pretty much the best you can do for goldfish - huge area for biological filtration

Thanks for the heads up, something else to think about for this tank then!

Cheers.

i have a undergravel filter before and i didnt use the air bubbler. instead, i put a pump into the tubes so its powerful enough to draw water from the bottom back up to the top. it worked wonderfully for me. when i switched to a bigger tank. the bottom of my tank was filled with bio bugs.

I have two 30 gal tanks with goldfish. I have them each set up with a Penguin 350 and a Emperior 280. Both have bio-wheels and the Emperiors have room for extra bio-material. The combination of the two filters work really well.