Undergravel filters

bam

New Fish
Jun 21, 2016
9
2
3
#1
I have a 29 gallon tank that has an Aquaclear 70 power filter. I was just at a mom and pop pet shop, and he told me that I should also have an undergravel filter. I'm just wondering what people think of this advice.

I had an undergravel filter many years ago on a 25 gallon and I hated it. Are they better now? It was such a disgusting mess. I've heard them referred to as undergravel filth collectors.

Thanks.
 

CAPSLOCK

Elite Fish
Jul 19, 2004
3,682
33
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Cape Cod
#2
They are indeed disgusting filth collectors. And you need to remove everything to attempt to clean them. As far as I know, the technology hasn't changed in many years, so the new ones are just as gross as the old. HOB filters are much easier and more maintainable. An HOB and a gravel vacuum are miles better than undergravel filters.

This would lead me to suggest you take any other advice this store offers with a grain of salt...
 

Likes: bam

bam

New Fish
Jun 21, 2016
9
2
3
#3
Thanks for your reply. I had the same thought. This was the same shop that told me it's ok to have six fancy goldfish in a 29 gallon tank. I didn't want to argue so I didn't say anything, but I know better.
 

FreshyFresh

Superstar Fish
Jan 11, 2013
1,337
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38
East Aurora, NY
#4
I used UGFs 30yrs ago, but I wouldn't even consider one today. Looking back, they really serve no purpose other than *maybe* flowing some water across your substrate to make some nitrifying bacteria happy. Your AC70 HOB is a great amount of filtration for a 29g. Squeeze out the sponge and swish the bio bag weekly when you do your water change. Add a cheap sponge bubbler as some secondary/backup filtration if you have air running to your tank.
 

FroggyFox

Forum Manager
Moderator
May 16, 2003
8,589
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Colorado
#5
I ran a reverse UGF for a while a few year ago in conjunction with a HOB filter and I don't think you can beat the bioload capacity of using all (or a large part) of your gravel as a filter. That being said, when I got tired of looking at the towers I had to completely rip the tank apart to get the plates out and I don't think I'd voluntarily put another one in a tank, regular or reverse. I think the bio capacity is why most old school fish stores still use them (I know my favorite one does), but I don't think I've heard them actually recommend using them in home tanks, that'd raise a red flag for me too.