# how often does aqua soil need to be replaced?



## o snap its eric (Jan 12, 2004)

A year? I'm worried about the soil being depleted of all its' nutrients.


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## Gatekeeper (Feb 20, 2007)

Are you dosing the water? Fish waste and decaying plants should be giving some mulm to the substrate to feed the plants.


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## plantbrain (Dec 15, 2003)

It's not an on/off type of thing, the depeletion is gradual and depends on you and your frequency of redoing things also. Even after almost 2 years, the ADA As still grows HC etc with no contribution from the water column........(used the Dry start emergent growth method) and the other area where new ADA As was added, have much better growth(about 500-600% more). Still, the old stuff did grow the plants fairly well. So there is clear depletion occurring over time and it's easily tested and measurable(pot test work excellent for this in terrairums, this rules out water column interactions, very easy to answer such sediment type questions independent of water column nutrients/CO2 etc)

However, for many aquarist, adding water column ferts should extend the lifetime as well as help the plants grow better in general.

Even with no nutrients in a sediment, this works very well also.
This way both bases are covered effectively and make the method for nutrient delivery pretty easy(fish waste + water column ferts(light or heavy)+ rich sediments).

Lower light= lower rates of growth, so that will also extend the life.
Quite a few obvious variables including human's perception and goals.
There is no set point for an effective life time where one should replace a sediment type. Sort of an eyeball thing. Or, you could do a pot test and compare the differences over say 8 weeks in a small glass terrarium with some old and new sediment to see.


Regards, 
Tom Barr


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