# Eco-Complete and Gravel



## aquariageek (May 27, 2006)

I am changing a 10 gallon with gravel to eco complete.

I read that some leave a very small layer of existing gravel underneath the eco-complete, to help with compacting. On EC's website it says it does best as the sole substrate...but perhaps that is just good marketing 

Is it advisable to leave a layer of the existing gravel and pour the EC on top of that?


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## Catastrophi (May 23, 2006)

The only reason I can think of leaving a small layer of gravel at the bottom is beneficial bacteria. Other than that. I'd make it 100% eco-complete.


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## erijnal (Apr 5, 2006)

Don't replace all of your substrate in a day. You'll be getting rid of all the beneficial bacteria that has gathered in your gravel. Replace the gravel section by section, gradually. I've heard replacing a portion every week or two is what's generally recommended. Replacing it this way will give time for beneficial bacteria to colonize the new substrate, so you won't have a huge spike in ammonia or nitrite after a large replacement.


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## John N. (Dec 11, 2005)

You can replace section by section, or save up some of that "mulm" leftover debris/muck that you can siphon from the existing gravel. 

Layer that "mulm" on the bottom, and place the complete bag of Eco complete on top. You can drain the liquid from it, or simply dump it in. I dump it in. Anyways, the mulm will jump start your bacteria colonies, and in a day or two you should be fine. Putting in a bunch of plants will soak up the excess nutrients, and prevent the cycle. 

Compaction issues aren't very problematic in my opinion. You'll always end up with some compaction, but with a light stir every month or so, you'll won't have a problem squashing roots, or creating those aneorobic areas. So unless you want the extra height of placing the gravel layer on the bottom, then I would just leave it out.

-John N.


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