# COMPOST AS SUBSTRATE



## Mr. Z (Sep 4, 2021)

Hey all
I have doubts about aquarium substrate.

I have a compost that had been decomposing for years and now smells like "wet soil". Can i use this COMPOST directly as substrate with a gravel cap or do i need to add normal garden soil to this COMPOST in 50-50 ratio (to lower nutrients) then cap with gravel ?

All recommendations are welcome.

Thank you in advance.


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## mistergreen (Mar 3, 2007)

Compost has a lot of nutrients in it which will cause a lot of problems like algae and anaerobic conditions. You can use 1/3 of compost and the rest can be sand and small gravel mix and then cap it all with sand or gravel.


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## Michael (Jul 20, 2010)

If your compost is home made and really has been decomposing for years, it is probably safe. You can still mix it with ordinary soil or sand or one of the high CEC substrates if you are cautious. Lots of things are called "compost"--the high nutrient fresh commercial "composts" are the ones likely to give problems


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## Mr. Z (Sep 4, 2021)

Michael said:


> If your compost is home made and really has been decomposing for years, it is probably safe. You can still mix it with ordinary soil or sand or one of the high CEC substrates if you are cautious. Lots of things are called "compost"--the high nutrient fresh commercial "composts" are the ones likely to give problems


The compost i described above is completely homemade from plants and animals waste since last 2 years plus and now smells like wet soil
Thanks a lot for the responses


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## U4IK (Apr 22, 2021)

I highly recommend you ”mineralize” the compost to eliminate the animal waste. I think it may cause you algae problems with time. From the forum home page, search: How-To: Mineralized Soil Substrate. Then, use it and mix it with something else as Michael suggested above. Others chime in, what do you think?


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## Mr. Z (Sep 4, 2021)

U4IK said:


> I highly recommend you ”mineralize” the compost to eliminate the animal waste. I think it may cause you algae problems with time. From the forum home page, search: How-To: Mineralized Soil Substrate. Then, use it and mix it with something else as Michael suggested above. Others chime in, what do you think?


Thank you


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## Mr. Z (Sep 4, 2021)

Mr. Z said:


> I'll read that page. Thank you


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