# substrate life



## jeff61 (22 Nov 2016)

moving from marines I am looking to set up my 1st planted tank about 250lt  -   but what happens in 3 yrs when the nutritional value of the substrate has gone - do I have to replace it as I imagine this would be a complete strip down


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## roadmaster (22 Nov 2016)

Seldom see tank's left to run but a few month's before re-scaping it seems.
Dosing water column with nutrient's,adding clay or peat based substrates/soils, with moderate to good CEC ,root tab's,can get you a little more mileage.
I run low tech soil based tank's and usually do complete strip down every couple year's.
Been experimenting with soil supplement's  like Green sand,Azomite,safe-T-sorb,in a effort to get a bit longer life from the dirt.


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## dan4x4 (14 Dec 2016)

roadmaster said:


> Seldom see tank's left to run but a few month's before re-scaping it seems.
> Dosing water column with nutrient's,adding clay or peat based substrates/soils, with moderate to good CEC ,root tab's,can get you a little more mileage.
> I run low tech soil based tank's and usually do complete strip down every couple year's.
> Been experimenting with soil supplement's  like Green sand,Azomite,safe-T-sorb,in a effort to get a bit longer life from the dirt.



I also run low tech, I read the ecology of the planted aquarium and it told me that I shouldn't add fertilizers or root tabs. Why?

When I set up my new tank Im definately going to add red clay and more bone meal. I was wondering if there would be any advantage to adding another substrate even root tabs or one of these artificial soils?


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## roadmaster (15 Dec 2016)

Soils naturally are comprised of mostly organic matter,  so as the matter is processed biologically,nutrient's are available for plant's to draw from.
How long they are available month's/year(s) depends on plant mass drawing from the soil,temps,light energy,fast or slow growers,etc.
Could easily run low tech with soil base for many month's before considering adding nutrient's  via water column or DIY root tab's (see osmocote)
I mix soil and add amendment's as I choose with some general idea or purpose as to what will be the effect, and then cap it .
If I were starting with inert substrate such as sand or fine gravel,I would either place root tab's in the substrate (sparingly), or dose water column with nutrient's from the outset.
Would  always begin with as many fast growing plant's although they may not be the plant's that I ultimately end up with.
I seldom move plant's once I place them in the tank lest I create more of a mess than I care for with unleashing all manner of organic matter from the substrate in doing so.
Just sayin.


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## dw1305 (15 Dec 2016)

Hi all,





jeff61 said:


> but what happens in 3 yrs when the nutritional value of the substrate has gone - do I have to replace it as I imagine this would be a complete strip down


You don't have to, you can always feed via the water column and because you don't need to vacuum the substrate in a low-tech planted tank the substrate will mature biologically over time. 

I think the nutrients will have gone fairly quickly from most substrates that are initially nutrient loaded, the nutrients have to be water soluble to some degree to work as fertilisers. 

"Active substrates" have a cation exchange capacity (CEC) that allows them to initially replace more strongly bound cations (usually Ca++ etc) in the water with less strongly bound ones (K+ or H+) on the exchange site, but they won't stay active for very long, although they potentially can still exchange even strongly bound cations.   

This is Stephan Tanner on <"Aquarium Biofiltration"> it relates directly to Matten Filters, but exactly the same processes happen in the substrate. 

cheers Darrel


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## roadmaster (19 Dec 2016)

In nature, soils are privy to processes that aerate and replenish them such as earthworm's,grub's, that eat and excrete their waste back into the soil's,and composting of leaf litter,bird dropping's,solid waste from animal's etc.
In my aquarium's  I have snail's,shrimp's,fishes that I feed, that perform similar function but not nearly on the scale of what nature can provide ,so I add a little fertilizer's to substrate and also the water column on regular basis to help compensate for possible nutrient shortcoming's  over time.
Light energy is on low side in my low tech tanks so it is easier than perhaps high energy tanks where demand is maybe greater.
With fauna in the tank I do not think substrate will ever become totally depleted.


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