Re: "rich" substrate & fertilizer

> From: Don Funk <donfu at microsoft_com>
> The plants that I am finding that do OK in lower 
> light conditions require a "rich" substrate.  

Specifically what plants do you have in mind? You might be talking
about Cryptocorynes or Aponogetons. Both of these families have
species which range from easy to very difficult to grow.

I suspect the substrate additives you mentioned are probably similar
to laterite. "The Optimum Aquarium" is a good book to read on the
subject of laterite. There are extensive discussions of substrates
in the archives of this mailing list; search for articles with
substrate, laterite, vermiculite, soil and peat. You can supplement
macro-nutrients in your substrate with fertilizer tablets designed
for aquaria. One formulation successfully used by Jim Kelly combines
vermiculite, a small amount of ordinary soil and pond fertilizer
tablets covered by a layer of sand/gravel. I use a variation of this
in one of my tanks. There is a fair amount of material available
on this subject from Jim Kelly. I posted a fairly extensive article
in issue 1-260 entitled: "A discussion of substrate additives"
which was the Aug 23 digest. Some good discussion and no small
amount of controversies arose from this and other articles. :-)

> I have noticed that several people here add several drops of fertilizer 
> everyday to their tanks.  Does anyone have any suggestions on a brand?  
> Currently I add the tablets.  Do I need liquid also?

There are a large number of chemical nutrients which plants require
in minute concentrations. Potassium (K) is an important one as well
as iron (Fe), magnesium (Mg) and others. Flourish is a good, low
cost, highly concentrated liquid nutrient supplement which I
currently use. Tropica Master Grow is an excellent one which lists
its constituents and their concentrations. Dupla also has excellent
products but at higher price. There are many, many alternatives.
You should use a chelated nutrient formulated specifically for
planted aquaria or do a lot of research if you plant to mix your
own. Some of the members on this list have researched this and
found sources for concentrated, bulk supplies of chelated nutrients.
You can have many hours of reading through the archives on this
subject too.

>  Comparing my plants to the diagrams in the books, my 
> plants all seem to be tall and "lanky" and don't have the rich dark 
> green look(very slight greenish-yellow).  The leaves at the bottoms 
> have all fallen off, yet the tops look nice.

It may be that you have a K, Mg or Fe deficiency causing the yellowish
leaves. You should cut off the good parts of your Bacopa and replant
these. Discard the old, lower stems. This is part of stem plant

> Also about mid point on 
> some where the leave have fallen off, roots have started to grow.  I 

These roots are typical behaviour for Cabomba and Bacopa.
Just replant the tops of anything that looks ugly. After a while
your plants really improve their appearance.

> rarely clean the bottom of the tank with all the plants growing, but 
> change 25-30% the water about every 10-12 days which keeps the tank 
> very clean. I don't have any problem with algae above the "gravel 
> line".  Beneath the gravel there is a dark algae growing which I can 
> see looking though the glass on the side where air bubbles also form in 
> the gravel...should I worry about this?

Hmm, those bubbles could be poisonous sulfide gases (H2SO4) which
are formed by anaerobic decomposition of excess organics in your
substrate. Is this an old tank perhaps with an UGF? Gas bubbles in
the substrate indicate you should gravel wash the substrate more
frequently or may mean there is insufficient circulation there.
Lots of rooted plants also help to induce water flow into the
substrate and prevent this.

 Steve Pushak - spush at hcsd_hac.com - Vancouver, BC, Canada