Bubble production, Dangers, and Substrate

Subject: Re:Homework assignment: Bubble production and water motion

> I noticed one day that, if I got the water rocking back and forth
>in the tank by rhythmic pushing at one end, bubble production slowed down
>and stopped while the water and the leaves of the plant were in motion, but
>when things got still again, bubble production started up again.
>Since it is not likely that these gentle motions inhibit photosynthesis,
>there must be some other explanation.  I have my theory, but I would like
>to hear yours first.

OK, I'll bite.  My guess is that without circulation, the water right next
to the plant leaves was becoming super saturated with O2 and the bubbles
were being released.  When you rocked the tank, the water started to
circulate enough that the O2 produced was dissolved into water with a level
of O2 below saturation, so that even though the O2 was still being
produced, you didn't see it.


Subject: Dangerous Hobby!

>I thought living in Los Angeles was dangerous, never mind going near my tank!
>What with the danger of exploding PMDD, exploding CO2 cylinders, exploding 
>lights, electrocution from a DIY substrate heating system and not to mention 
>acquiring some sort of deadly tropical disease from the tank water, I
might as 
>well call 911.  To think I allow my two-year-old sleep in the same house
>all this danger.  Relax and enjoy!!

You forgot a couple.  Think of the danger of throwing your back out while
carrying in that new 125G tank... or dropping one of those rocks on your
foot... or cutting yourself with the razor blade when you're cleaning the

Subject: Advice on Substrate

>I've been browsing for a month now, trying to learn as much as I can
>before I set up my 140 gallon tank. 50"x27"x24" planted aquarium.
>I would like to use regular aquarium gravel, I've read where some folks
>do this, and wonder if adding anything to the gravel would improve changes
>for success? 

Just about _anything_ added to your aquarium gravel will improve chances of
success.  Plain gravel is probably the worst substrate possible for plant
growth until it is old and full of fish poop.  Some of the options are
laterite, other clays, potting soil, garden soil, peat, and vermiculite.
Other people have other "concoctions" they try with greater or lesser

Laterite is probably the "safest" in terms of possible mess and potential
algae problems, particularly if this is your first go at a planted tank..
It is not the most nutritious, but with regular addition of trace elements,
will grow a wide variety of plants very well.
Karen Randall
Aquatic Gardeners Association