# Gravel in aquariums = bad for plants?



## bpolley (Dec 29, 2006)

I just bought pounds and pounds of gravel for a new 55 gallon aquarium that I had planned to plant aquatic plants. I bought first -- now I'm researching. I should have done it the other way around. 

I already have around an inch of gravel over my underground filter. A. Can I add some soil and still have plants? B. Is an underground filter bad for plants?


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## joephys (May 9, 2006)

It depends on the gravel, if it is small (~1/4 inch or so) pea gravel it is ok for most plants. Grain size of about 1-2mm is the best choice. Very small plants won't grow in pea gravel, but most others will be fine. I have pea gravel and I have a dense jungle growing in my tank. I wouldn't use soil personally, it seems to me to be more trouble than its worth.

A lot of people will tell you that an undergravel filter is bad for plants. I have seen quite a few tanks that have undergravel filters that have great looking plants. I haven't personally ever used them.


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## trenac (Jul 16, 2004)

Welcome to APC :yo: 

I personally would not have choosen a under gravel filter for a planted tank, but it can be done. One drawback will be plant roots getting wrapped around the filter, making it difficult to remove or move plants around. Another drawback is having to use a larger gravel, rather than a smaller gravel (2mm) which is best for a planted tank. 

However gravel is fine to use in a planted tank. The majority of plants take their nutrients from the water column. So make sure that you are adding needed ferts from day one. 

One thing you may want to do is check the gravel for leaching, which will cause problems with the water parameters. Do this by removing some gravel and adding some vinager to see if it fizzes. If it does then the gravel contains carbonate minerals.


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## John N. (Dec 11, 2005)

To chime in to the above, if you want to add real soil, and go for an El Natural type tank where soil and minimal waterchanges are involved then I suggest you visit the El Natural forum ongo APC, and check out some of the stickies and threads there. Here's a good thread to start.

Gravel in generally okay for the tank, 2-3mm size grains are ideal for planting as they will hold the plants down better. Any bigger you'll find it more difficult to keep the plants down. In terms of nutrient needs, adding fertilizers like the Seachem fert line or dry ferts (gregwatson.com) to the water column is all that is really needed for most plants.

Lastly, undergravel filters (UGF) are not ideal for a planted aquarium, but as said above it can be done with careful cutting of the roots when replanting. If I were starting a fresh, I wouldn't have a UGF and just go plain substrate and a canister or Hang on the back (HOB) filter. You'll be surprised how deep the root system can go (over 4 inches deep).

So, a fine gravel bed of 3 inch depth, and water column fertilization will get you going perfectly fine. If you want, you can spring for the premium substrates like Eco complete or Flourite, but it isn't all that necessary. A good cheap alternative would be soilmaster select (see substrate forum).

-John N.


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## hoppycalif (Apr 7, 2005)

Garden soil with an undergravel filter is a problem. That kind of filter circulates the tank water thru the substrate, so the nutrients in the soil that are fine for the plant roots, but a problem in the water, will be in the water. But, just because you put the UG filter grid in doesn't mean you have to hook it up.


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## fishfan (Feb 19, 2006)

I think it saves time and money down the road if you use a nutrient rich substrate, but as the above comment mentioned, the only real problem with regular gravel is the size of it. If the pieces are smaller, the plants will stay put better and grow. Plus you can always get those tab fertilizers for plant roots to bury in the gravel.
However, someone on another forum I was reading said they grow java ferns in regular gravel and claimed they were growing better (in this person's tank) because the runners were spreading out under the gravel. So this person put all their ferns in the gravel instead of attaching them to driftwood.


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