Following the advice of my neighbor, one month ago I set up a 15 gallon
planted tank with 1" potting soil and then 1" of black quartz. This turned
out to be a big disaster. The fertilizer fueled massive algae growth. The
potting soil turned the water brown/green. Finally, two shrimp started to
die (I saved them by putting them in my neighbor's tank) and a bristlenose
died. Now I follow the advice of this group instead of my neighbor!

I want to rebuild my tank without the potting soil. I bought a special
substrate for plants that is similar to potting soil but is safe for
aquariums. It's called JBL AquaBasis Plus
(http://www.jbl.de/uk/aqua/uk_20212.html). Here's what it says for this
substrate:

"Contains all essential nutrients such as iron, minerals and trace elements.
The clay particles act as a nutrient store, binding excess nutrients and
releasing as required.
Does not require mixing with gravel.
Does not contain nitrates and phosphates which promote the growth of algae.

JBL Aquabasis plus contains the full range of vital nutrients as well as
iron and trace elements which aquarium plants need for healthy and strong
growth. These nutrients are provided in depot form and are fully accessible
and available to the root of the plants. JBL AquaBasis plus promotes rapid
rooting and results in healthy and strong root development."

The directions say to cover it with gravel or sand. One person told me to
skip the special substrate and just use sand only. I'd like to get some
feedback on using sand only. The advantages are that it's easier and the
layers won't mix. The disadvantage is that I do not believe the plants will
do as well. This probably isn't a big issue because I just want a few
plants (it's a small tank and the light is only 15 watts so I'm very limited
in the plants I can have) and I don't need them to grow like crazy. I just
need them to not die. I know I can add iron tablets to the sand if needed,
and some Malaysian Trumpet Snails would keep the sand stirred up and
aerated.

So should I return the special substrate and go with sand only?

Thanks a lot for your advice,
Michael