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Re: Newbie Designs and disrespected substrates

In reply to Chris, Arthur wrote:

> The most bang for your buck, by far, will be to
> purchase a co2 system.

> 1. light
> 2. co2
> 3. ferts
> 4. algae consumers
> 5. substrate

and Dennis responded:

> Just out of curiosity, why does substrate seem to always come last? After
> reading here a couple of months, I get the impression that substrate is just
> something to hold the plants in place. 

I will remove algae consumers from the list, as they are a usually an 
insignificant problem to find or afford, and their role in some tanks is 
fairly small.

Plants are oddly missing from the list.  Chis could spend several hundred 
dollars planting out a 120 gallon tank, so perhaps the plants themselves 
should go on the list. In even the simplest tanks, nonalgae-eating fish are 
so important to maintaining the plants that I think they should just be 
grouped together.  I'll call the plants and fish grouped together the 

Sometimes people -- for good reasons or bad -- want to replace their 
low-cost, easy to get tap water with something else.  In that case, then 
water has to go on the list too.  Water treatment systems necessary to 
support a 120 gallon tank can cost a lot of money and/or be difficult to find 
and assemble.  That isn't a general case so I'll leave it off the list, but 
it is something to keep in mind.

The list then includes (in alphabetical order) CO2, Ferts, Light, Occupants 
and Substrate.  Depending on your priorities and the methods you tend to use, 
the list can be ordered several different ways.  The list can even be 
shortened.  It's all up to the aquarist.

The ultimate low tech tank gets enough natural light to grow plants.  For 
that  tank the list is very short:

1. occupants
2. substrate

Quite a few plants are not rooted in a substrate, so substrate gets second 

Any other tank must be provided with light.  There is no aquarium  where 
plants will grow without light.  For the next step into artificial life 
support the list becomes:

1. light
2. occupants
3. substrate


4. nutrients

A good substrate plus usual fish feeding can supply the plants with 
nutrients, so fertilizer is optional and isn't needed in many tanks.  If the 
light on this kind of setup is very bright then thorough aeration becomes 
essential.  Without good aeration the CO2 level in a brightly lit tank will 
drop to 0 and the pH will go to 9 or more.  Those are hostile conditions for 
many plants and some animals.

If the aquarist wants more growth out of the tank, but isn't very interested 
in aquascaping then the light must be brighter and CO2 might be added.  
Assuming that the aquarist uses a fertile substrate the list now becomes:

1. light
2. occupants
3. substrate
4. nutrients
5. CO2 

CO2 is secondary in this setup.  The aquarist might use DIY CO2, never really 
worry about the  CO2 levels and regularly let the CO2 generator run flat.  A 
lot of the CO2 and nutrients in a setup like this can be provided by the fish 
and substrate.

If the aquarist is interested in aquascaping or is in the habit of moving 
things around a lot then a fertile substrate isn't practical and the whole 
list gets shuffled by the need to supply CO2 and nutrients without the help 
of a fertile substrate.  In that case the list becomes:

1. light
2. CO2
3. nutrients
4. occupants
5. substrate

That looks a lot more like Arthur's list.

In my experience, approaches that are intermediate between these last two 
lists don't work very well.  The combination of an infertile substrate with 
low or erratic CO2 levels and limited fertilization mostly gives you algae 
and nutrient-deficient plants.

Often people will use an infertile substrate even when they don't intend to 
aquascape or move plants around all the time.  Often that's just because 
better advice wasn't available when they were setting things up.  If that 
happens then a UGF can be used to get and keep some fertility in the 

So take your pick.  I guess the substrate can be as important or unimportant 
as you want it to be.

Roger Miller