Lets talk UG filters

[Paul B]

Lets talk about Undergravel filters, no really. Old technology? maybe but so is running water. When we got tired of going outside to pump water, we didn't stop using water . We invented faucets. OK not a great analogy. In the beginning of the aquarium hobby, which was right after WW2 we all kept goldfish and guppies. The first thing we did was to put in an undergravel filter, why? Because it worked. Originally we thought it was a mechanical filter and we loved mechanical filters because we liked to filter out particles. Water quality didn't matter as long as we could see the fish. Clear water was also essential to locate the dead fish, and we found a lot of dead fish.
Not because of the UG filter, but because we were using it wrong. We read the instructions and that was our first mistake. :crazy1:The people who invented and sold UG filters were not at fault, they also liked to filter things and an UG filter does that fairly well. Unfortunately, for some reason we didn't want to think of all that stuff that was filtered but still in the tank. We must have been busy watching those Ann Margaret movies.
But in our defense, freshwater systems do great with UG filters. I am not sure why but they do.
Then we all got high class and changed most of our systems to salt water. We loved our UG filters so we kept them, after all, they worked great and "filtered" out all that "stuff" that we figured we needed to filter. Then there was Bonanza on TV and we again forgot that an UG filter does not remove anything.
Boy were we stupid. Thats when 99% of us removed the UG filter. But there is something I like to call those people, and that is "wrong".
The UG "filter is fine, we were the problem. It is not a "filter" even though that is what it reads on the box, it is a water treatment system.
If we use it as a filter, our tanks will crash, guaranteed.
Robert Straughn (The Father of Salt Water fish Keeping) advocated UG filters as the greatest invention since tap water. The man was a genius but he didn't know the reason the UG worked.
The UG "System" will only work if we keep out the particles or as we like to call it "detritus" (dirt, crud, shmutz etc.) The gravel on the bottom of a tank vastly increases the real estate that bacteria can live on. Bacteria are like us, they like water front houses with continous fresh calm breezes and lots of easy to get food. Gravel is perfect for them and, like apartment buildings, they can live on top of each other without getting in each other's way.
Water with no particles flow past those bacteria, the bacteria process out what they want, which depending on the type of bacteria that could be nitrate, nitrite, ammonia
or Harvey's Brystal Cream. Too many particles and the bacteria will think they are living in a slum and the water flow along with their oxygen and food will stop.
Some bacteria are lucky and they like it when there is less oxygen, they have larger noses to collect oxygen, maybe not, I don't know, but they process nitrate in the absence of oxygen.
So some detritus in the gravel will limit oxygen and actually help those bacteria convert nitrate and detritus is going to get in there no matter what we do.
The best way to run a system like this is to take the UG filter and throw out the instructions. Then build a manifold above the water. Connect the tubes from the UG filter to the manifold and pump water into the manifold so all the tubes get a slow even flow. The water going into this manifold should first be strained to kep out those large smutz particles. Run this arrangement slow. The slower, the better.
Will this run for fifty years with no maintenance? Absolutely not. A few times a year you need to stick a canister filter of some type in there and stir up the gravel. It helps if most of the rock is not laying on the bottom. That doesn't look good anyway so figure out how to do a dynamite aquascape job.
It may get you a girlfriend, maybe not. :wave:

 

[KafudaFish]

Thank you Paul.

 

[jpfishfan09]

But undergravel filters look so ghetto...

 

[tkeracer619]

Can someone please sticky this so when Paul wakes up next to an empty bottle of sherry he knows where he was last night!

Pay attention to what this man has to say. Because he knows his stuff!

 

[pmrossetti]

guy at my lfs has all 30 of his home tanks on reg flow ugf. swears by them. they're not reef tanks tanks though.

he won't keep reefs. thinks they're environmental disasters. only hardy fish.

 

[Paul B]

But undergravel filters look so ghetto...

Thats because you are supposed to put it under the gravel where you can't see it, not on top. :lolspin:

an empty bottle of sherry

That was merlot

 

[jeff@zina.com]

Under gravel filters work great. Other, newer, technology works better and is easier to maintain.

Jeff

 

[Paul B]

Other, newer, technology works better and is easier to maintain

Which technology is that and how long does it last? I may have been in a coma for the last 40 years :uhoh3:

 

[RocketSurgeon]

Which technology is that and how long does it last? I may have been in a coma for the last 40 years :uhoh3:

would the UG be similar to today's wet/dry bio ball that we can actually hide under the stand?

 

[Paul B]

would the UG be similar to today's wet/dry bio ball that we can actually hide under the stand?

No, it goes under the gravel in the tank.
Here is my gravel and you can see the tubes going into it that are used to pushwater under the gravel. This was from my last and third cleaning.
Every ten years or so I re aquascape and remove the rocks. Once I went almost 20 years.

 

[psteeleb]

Paul - nice write up
as an old school kind of salt water nut I've used UG and RUG's on many tanks. As you point out the main reason they failed as when used as a filter they clogged creating dead zones and eventual anaerobic areas that when disturbed would crash the tank. Much of this concern was fixed with the Reverse UG, as it help to eleminate the dead zones but RUG's were soon replaced with wet drys (allthough I never used one, as they just seemed to be an expensive alternate to good maintainence)

Over the years I found it best to always stir up the sand bed and filter the gunk out of it. Often I did this as part of the water change but also used fiber and DE polishing filters.

Although I'm good with current practices that have moved away from the UG filters I have often thought about setting one up again. I still am kicking around an old design I came up with and used in the late 70's that was a reverse UG with a back panel that acted like an overflow. I think this modified RUG would also make a great pod factory using the proper grained sand and using it as a low flow seahorse tank.

 

[RocketSurgeon]

the principal is not the same? you are pushing water through bio balls, where bacteria convert ammonia and nitrite?

You are pushing water through sand, essentially doing the same thing.

Both systems crash if you allow detritus to build up.

they function very similar to me, it seems. I must be missing something. The UG is hidden under gravel, the wet/dry is hidden under the stand.

 

[wildman926]

The one thing you fail to mention, is the detritus that builds up over time beneath the undergravel filter system. No matter what flow you provide, it will build up.

I have used for almost 20 years, an undergravel filter with reverse flow power head kits (penguin, 1140 powerheads) on my 150g fw filled with African Cichlids. Each time I have broken down the tank to move, etc, underneath the plates it was completely full of detritus. I performed a full grave siphon every 3 months, but the detritus was still there. This may be ok for fw as nitrates do not affect the inhabitants, but not sw.

An ugf has no place in a sw aquarium.

 

[Paul B]

Although I'm good with current practices that have moved away from the UG filters

Ug filters fell out of favor for the reasons I stated, I know, I was there. There is no money to be made from the devices because they are very cheap.

Over the years I found it best to always stir up the sand bed and filter the gunk out of it.

I do this a few times a year with a power filter, it is just good maintenance and no system will last without maintenance.

the principal is not the same? you are pushing water through bio balls, where bacteria convert ammonia and nitrite?

No, the principal is not the same.

they function very similar to me, it seems. I must be missing something.

What you are missing is that a wet dry works in air. Not submerged. The air allows aerobic bacteria to bathe all parts of the wet dry and only aerobic bacteria will live. Those are very efficient at converting ammonia but will do nothing for nitrate.
A properly run RUGF on the other hand uses detritus to reduce nitrates.
Think of a RUGF as a wall built out of roundish rocks used as a dam or levee.
Water will of course rush through. But if you push tee shirts (detritus) into the crevaces, you will slow down that water. (Sand Bags do the same thing, just slow but do not stop water, I know all about sand bags as I filled and lived in thousands of them in Viet Nam) The areas that there is reduced water flow will grow anerobic bacteria. There will always be some circulation in these areas and that is good because water will not get processed if it does not make it to the bacteria. Detritus is not like clay, it is more like lint and kind of pourous. Yes, if you let it go for decades it will probably clog completely but that is why I say to stir up the gravel, where you can reach by just blowing water at it with a power filter.

Both systems crash if you allow detritus to build up.

Have you ever seen a slow running RUGF like I mentioned crash? I have not.
Mine was just 40 years old last March. It has not crashed yet and I have had 24 urchins all spawn at the same time so the water looked like half and half and smelled like rotten half and half. I also had a huge carpet anemone die while I was not home and the tank stunk worse. After it cleared, everything was fine.
When the power went out on the east coast for 5 days, nothing happened at all.
My nitrate is 5 and I only change a little water about 5 or 6 times a year, so where is the nitrate going? I add water from the sea along with mud (for the bacteria) pods, seaweed, crabs, snails and shrimp almost every week in the summer.
I removed the rocks a couple of weeks ago to re aquascape and catch two fish I wanted to remove. I also wanted to add some cement rock supports that I built. After I removed most of the water and stirred the gravel, I was surprised that it was no where near as dirty as I thought it would be. And that is after years of use.
You can see in the picture above. That was a few weeks ago. The gravel is not that dirty and I stirred it up vigouresly.
My purpose is not to get anyone to use a system like this. I have no stock in UG filters. But I continousely hear people say that it has no place in saltwater and I have never heard of any of them crashing. How many DSBs crash? I would say after ten years, just about all of them.
But this system must be used properly. I myself used it incorrectly in the beginning and what a mess. The UG is not bad, the way we use it was bad.

In this picture I have drained most of the water. I shook off the rocks before I removed them and I violently stirred the gravel. It is clowdy for sure but not black like you would expect after years of water being pushed through the 40 year old gravel. Most of that white stuff came out of the rocks I shook. I threw out the last few inches of water, then I put back most of the water that I removed and all is well. The entire job took me four hours.
I don't consider this work as I like to re aquascape every so many years. I build a lot of rock and I like to add it and remove other pieces that I get tired of. With this system I can stir it up as much as I like.

on my 150g fw filled with African Cichlids

You are correct, African Ciclid tanks will not work well with this system, but I am talking reef not cichlids

 

[psteeleb]

Ug filters fell out of favor for the reasons I stated, I know, I was there. There is no money to be made from the devices because they are very cheap.

I was also there, and agree with you but I may have stated it differently.
In the early 80's (or mid 80's) the big new thing that everyone "had to have" was the (IMO) over priced wet drys. Back then I stayed with UG as I just didn't see the gain of the wet dry (much less forking over some big bucks) as long as the UG was maintained.

 

[Paul B]

I also had a wet dry but I very rarely buy anything for the tank so I built it for almost free. I kept in the UG filter but I thought the wet dry was cool loking with the rotating spray bar and all.
I still have it on my tank but I cut it down smaller and now use it for an evaporative chiller. It works great. I like to recycle also.

Here is my tank a couple of days after I re aquascaped. The fish all thanked me and love their new digs.

This was my wet dry in the 70s. I cut it by about 2/3s and added plates and a fan so it functions as a chiller.

And here is one of the cement covered PVC rock supports I wanted to add under the reef structure. You don't see it in the tank, but this and a few others hold all of the reef off the substrait. I like the look of seeing completely under the rocks and it is much better for circulation.
Adding these supports was one of the main reasons I wanted to do this maintenance.
For me this is a hobby, and as such, I like taking it apart and tinkering with it. It is not stagnent like stamp collecting.

 

[pmrossetti]

i hope this isn't a dumb question but it probably is.

why is the rugf needed at all with the rock and sand? isn't that its own filter? add a hang on skimmer and aquaclear w carbon/gfo and go,no?

i think ugf went out when live rock came in because it covered up too much of the surface,no?

thanks

 

[Paul B]

why is the rugf needed at all with the rock and sand? isn't that its own filter? add a hang on skimmer and aquaclear w carbon/gfo and go,no?

Not a dumb question at all, but still a question. The rock and sand will sit there minding it's own business but if you don't circulate water to the lower parts, that area will not do anything to process water because there is no circulation, no circulation means no water is running through there so those areas are not helping much with de nitrification. Eventually the areas in the lower areas of the bed will fill with dead bacteria, detritus and crustacean shells, mostly from pods. We call that a DSB and DSBs have a limited lifespan. Also the creatures that we want to inhabit in our tanks will not populate the lower areas because of lack of oxygen. We want some areas to have reduced oxygen but we also want some water to get down there to be processed. If the lower regions become anoxic which they may eventually, there is a possability to produce hydrogen sulfide that could be a problem if we want to aquascape or maintain the bed. A RUGF allows us to disturb the substrait as much as we like whenever we want. A healthy substrait (IMO) has water flowing through it.
I am not thinking of a tank 5 or 10 years old. Almost all of our fish live much longer than that. I am talking decades.

 

[KafudaFish]

The one thing you fail to mention, is the detritus that builds up over time beneath the undergravel filter system. No matter what flow you provide, it will build up.

I have used for almost 20 years, an undergravel filter with reverse flow power head kits (penguin, 1140 powerheads) on my 150g fw filled with African Cichlids. Each time I have broken down the tank to move, etc, underneath the plates it was completely full of detritus. I performed a full grave siphon every 3 months, but the detritus was still there. This may be ok for fw as nitrates do not affect the inhabitants, but not sw.

An ugf has no place in a sw aquarium.

Do you believe that it is an equipment issue or husbandry one?

 

[LouZ]

You mention gravel.....is SouthDown to fine for this ???? What type of pump are you using to push water ? How deep is the bed ? The thread is bring back flashbacks for me because my first SW tank was with a UGF used in the "normal" way.....fail....

Interesting about the platform.....I was thinking about the same....I'm setting up a 150H for anomones with a 6" DSB. I wanted the CUC full acess to the top sand area...