Under Gravel Filters

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When you hear those words does it make you cringe? Sort of similar to dial up internet and all of the "older" gadgets in life, many newcomers may not even know what those filters were. Did you ever have one? i can remember cleaning a tank for an older gentlemen about 20 years ago and I'm serious when I say I don't think that under gravel filter had ever been moved or cleaned. The gunk under it was dark brown and thick. What is your historic memory of these fine filters?

 

[BuffaloLake]

It was the only thing that I knew for years. Started out with tanks in the early 90’s in Stillwater, Ok. We only had one store that carried saltwater, and that’s what he carried. No live rock, just a 55 gallon tank with 6” of crushed dolomite and a Penguin powerhead in each back corner. Kept mostly predator tanks, but did manage a tank with a sea apple, a carpet anemone, a copperband, a yellow tang, a clown, and a coral beauty. That tank didn’t even have a light, just the overhead light in the room. Re-entering the hobby two years ago was a shock.

 

[saltwaterfish.com Verified Sponsor]

It was the only thing that I knew for years. Started out with tanks in the early 90’s in Stillwater, Ok. We only had one store that carried saltwater, and that’s what he carried. No live rock, just a 55 gallon tank with 6” of crushed dolomite and a Penguin powerhead in each back corner. Kept mostly predator tanks, but did manage a tank with a sea apple, a carpet anemone, a copperband, a yellow tang, a clown, and a coral beauty. That tank didn’t even have a light, just the overhead light in the room. Re-entering the hobby two years ago was a shock.

It amazes me the technology these days. I honestly can't keep up. I am sure you were shocked!!

 

[mfinn]

If I remember correctly the first time I saw one was for a freshwater tank back in the 60's.
Then my first salt water tanks used them in the 80's.
They did work.

 

[MC Blowfish]

My parents had one in our freshwater tank when I was a kid in the 80s. I sold a few when I worked at a pet store in the early 2000s. I wouldn't use one today.

 

[Uncle99]

When you hear those words does it make you cringe? Sort of similar to dial up internet and all of the "older" gadgets in life, many newcomers may not even know what those filters were. Did you ever have one? i can remember cleaning a tank for an older gentlemen about 20 years ago and I'm serious when I say I don't think that under gravel filter had ever been moved or cleaned. The gunk under it was dark brown and thick. What is your historic memory of these fine filters?

For me, simply the best filter configuration I’ve used in 40 years.

This is a 5 year old 65g with undergravel filter.

 

[Rob A]

My 300 lagoon is one giant under gravel fliter and I have a 160 that I'm in the process of setting up it too will have an under gravel filter. They are not Instagram ready so I think alot of people dismiss them. The amount of surface area available for bacteria cannot be matched with other filters. The other thing I think is funny is aquarium stores almost always use under gravel filter and sponge filters but will never try to sell you one.

 

[Privateye]

I haven't used them in reef systems, but I've used them in freshwater display tanks and saltwater quarantine tanks. It's not that I put them to use - they were already in place when I started caring for the systems.

They sure worked. The height differential while siphoning can be key for getting the debris underneath. A stronger siphon can often lift a lot of that up. Still, I don't use them in my tanks.

I am curious about using them in reverse though. I've seen it online but I haven't tried it myself. Basically you put a pump at the top of the air lift pipe. The pump has a sponge on the intake, and it blows water down the pipe, underneath the gravel. So clean water comes up from the gravel, and debris is caught by the sponge on the pump intake. I'm sure the sponge can clog quickly, but the idea of not needing to do any maintenance on the gravel is attractive. Then again, perhaps having an anaerobic zone in the substrate adds some benefit.

 

[saltwaterfish.com Verified Sponsor]

For me, simply the best filter configuration I’ve used in 40 years.

This is a 5 year old 65g with undergravel filter.

Wow!!! I wonder if there are others out there still using them!! I mean obviously it is working! Amazing tank!

 

[saltwaterfish.com Verified Sponsor]

My 300 lagoon is one giant under gravel fliter and I have a 160 that I'm in the process of setting up it too will have an under gravel filter. They are not Instagram ready so I think alot of people dismiss them. The amount of surface area available for bacteria cannot be matched with other filters. The other thing I think is funny is aquarium stores almost always use under gravel filter and sponge filters but will never try to sell you one.

I am so intrigued!! I thought it was a thing of the past!

 

[Rob A]

I haven't used them in reef systems, but I've used them in freshwater display tanks and saltwater quarantine tanks. It's not that I put them to use - they were already in place when I started caring for the systems.

They sure worked. The height differential while siphoning can be key for getting the debris underneath. A stronger siphon can often lift a lot of that up. Still, I don't use them in my tanks.

I am curious about using them in reverse though. I've seen it online but I haven't tried it myself. Basically you put a pump at the top of the air lift pipe. The pump has a sponge on the intake, and it blows water down the pipe, underneath the gravel. So clean water comes up from the gravel, and debris is caught by the sponge on the pump intake. I'm sure the sponge can clog quickly, but the idea of not needing to do any maintenance on the gravel is attractive. Then again, perhaps having an anaerobic zone in the substrate adds some benefit.

I'm seriously thinking about doing a reverse on the tank I'm setting up if for nothing else to see if I can see a difference between the two

 

[PapaFishRocks]

Years ago I ran one on my Cichlid tank. One day I decided to just remove it.

Few hours later, all the fish were at the surface struggling to breathe.

I learned an important lesson that day.