# Under gravel filters



## Steve McPherson (Aug 28, 2006)

Hi guys,
I'm an absolute beginner to the aquarium plant field and was wondering if anyone can tell me which plants, if any, will work in a 100 litre column tank fitted with an under gravel filter and topped with a standard twin tube light fitting. Thanks. Steve.


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## hoppycalif (Apr 7, 2005)

The plants that will grow depends on how much light you will have, what fertilizers, if any, you dose, and if you use CO2 and/or Excel.


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## Jimbo205 (Feb 2, 2006)

Steve, I had to learn myself the hard way. 
Undergravel filters do not work well with plants because the water flow through the substrate does something to the root hairs. 

Someone with an advanced understanding of biology could explain the details. 

I had to learn the hard way. 
The Local Fish Store kept telling me that I needed to take it out, but NEVER told me WHY!

When I finally tore it out, I had found that my Java Fern grew very well AROUND the underground filter grid. 
But would never grow on top of it. Go figure. 

Maybe some plants that do not have root hairs would work well. Or floating plants? Good luck.


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## joephys (May 9, 2006)

The idea with UGF's is that the increased oxygen in the substrate will react with some of the nutrient ions making them unavailable to plants. Most plant people say that UGF's don't work. I have never tried it, but I know of atleast two people that use RUGF's with planted tanks, and they love them.


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## Jimbo205 (Feb 2, 2006)

> I know of atleast two people that use RUGF's with planted tanks, and they love them.


 What kind of plants?


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## Tom Higgs (Mar 2, 2006)

The very high aeration of undergravel filters may make it difficult to maintain sufficient dissolved CO2. The bubbling will tend to purge it from the water. I guess if you keep the gas flow high enough / long enough you can make it work.


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## Jimbo205 (Feb 2, 2006)

Steve, the root hairs on plants interact with the substrate around them to break down the nutrients that are bound up. Cations I believe they are called. These are nutrients that have positive + ions. These get bound up in Soilmaster Select or soil. These have a very high cation exchange capacity. Aquarium gravel, sand and rock have a very low cation exchange capacity. 

I believe Aquabotanic (Robert Hudson's site) has a very good article about it. 

Anyway, the root hairs chemically react with the bioavailable nutrients in the soil or substrate surrounding it. There is a possiblility that the root hairs have a much lower pH and acidify the surrounding soil to release the nutrients. 

In any event, they need stability as they are very delicate. Similar to the root hairs and roots of vegetables grown in a garden. When grown naturally the roots and root hairs interact with the bacteria (millions!) and fungi (billions?) in the soil to absorb what the plants need. When the soil or substrate is disturbed it is like transplanting the plant all over again and the shock the plant goes through. 

You may want to use aquatic potted plants, plants bound to corkboard, rock or wood branches, or floating plants. Water Sprite, Water Lettuce and Giant Duckweed may work very well. 

You may also want to do a search for 'undergravel filters' and see what pops up. 

I hope this was helpful. 

I am just scratching the surface on this topic. Diana Walstad's book - Ecology of the Planted Aquarium is a very good investment and goes more into detail on these topics than I ever could. And of course there are many members on this site that are very advanced in the sciences that could give you EXTREMELY detailed explanations on this. 

I look forward to reading their reponses to your questions.


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## joephys (May 9, 2006)

Jimbo205 said:


> What kind of plants?


Too many to list them all, I think just about all of the major types.


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## fresh_newby (Mar 13, 2006)

I hope this helps, but
Karen Randall spoke at our NJAS meeting last week, and though it was very basic, it was targeting fish keepers to not be afraid to convert to a planted tank. Many of them had undergravel filters already. Though these are not ideal filters for planted tanks for many reasons, it is doable, at least for a while. It is tough to maintain good CO2 levels that way, but if you supplement with some excel, it should provide some added carbon for your plants that would otherwise outgas by nature of the filter. 
Also, if you choose stem plants with shallow root systems, you should be fine. Many stem plants, ludwigia spp and some Limnophila and Hygros have really shallow roots even though they are large-growing stems. There are ways around it for a basic planted tank. If you end up wanting to try species with large root systems, or a more high tech setup, it may need to be changedout in the future. Though I am not a fan of undergravel filters at all, it can be done. I would rather see you have a planted tank with an undergravel filter than none at all!


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## Jimbo205 (Feb 2, 2006)

> I would rather see you have a planted tank with an undergravel filter than none at all!


 Agreed, that is how I started out!


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## Steve McPherson (Aug 28, 2006)

Thankyou one and all for the great advice. As I said, my tank is a 100 litre column unit with undergravel filter and 3" of basic aquarium gravel on top. Lighting is via a twin 12" 8 watt Power Glo tube setup. I currently have a good number of Anubias Barteri plants growing on driftwood ( heavily planted)and I'm fertilising these with the recommended dose of Flourish. As I live in an area with very alkaline tap water, I'm trying to bring this back to conditions suitable for a few Tetras etc. The system has been running about 2 weeks now ......so far so good. Thanks again. Steve.


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## Jimbo205 (Feb 2, 2006)

Steve, do you have the ability to post a digital photo? 

I would love to see your aquarium. 

What is your pH? 

What recommendations have you received for fish that would do well in your area's pH level and local water? 
(From local fish stores or other sources). 

I like Tetras. 

I am also curious the fish that would do well in your local water.


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## Steve McPherson (Aug 28, 2006)

Hi Jimbo, sorry about the delay, I've been away working for a few days. 
My PH is around 7.6 - 7.8 but I'm trying to get it closer to 7. No one has suggested fish species at present, but I've always had a liking for all the Cat Fish, so would like to include a couple of them if possible. I'm doing a bit of research at present on what types of fish will survive our very Alkaline water in Sydney. I don't the ability to include pics at present, but I'm working on it. Since I last spoke to you I've decided to rip out the UGF and go with a Hang on the back type Power Filter. Because the tank is eight sided, I only have a bit over15cm in the hood opening on back to hang it on. I'm trying to find one with sufficient turnover rate that will hang in the space I have. I also have new leaves opening on the Anubias, so something must be right. I'll post pics as soon as I can. Thanks again, Steve.


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