Nitrates?

I know this is probably a controversial subject but I am still trying to get
a real grasp of what concerns I should have about nitrates. The opinions
seem to be diverse. Some say the number is not so significant so long as
the fish grow with it. Others say don't worry unless its almost off the
scale. Others say whoa 10ppm max, no 20 well no more than 30-50. I am
hopelessly addicted to my little fishes so I generally think I keep a pretty
good tank. Around 10x gph/tank size with penguin filters. Weekly water
changes and vacuuming. Test 2x/wk. No ammonia or nitrites. But my nitrates
do tend to be a little high (depending on who you talk to).=10-40 I think.
It seems you would have to be an accomplished artist to correctly interpret
those shades Frankly my budget is well suited to the inexpensive bio
wheels, but I am tempted to try canisters just so I can add some nitra zorb
or other additives, if it's really necessary. Of course then there are
other vets who say UG filter and a sponge filter, thats all you ever need to
add to a tank. The bottom line is I am going to have a tendency to want to
spend sparingly, add as little as possible and stock heavily and I am trying
to 'learn' to know how many fish I can handle safely. I am willing to put
in more time quicker than I am more money. I really do value each fish so I
don't want to learn by death rates. But, I also pond. From there I know
there are alway those who suggest much lower stocking rates, 'to be safe'
when much higher are possible if you know what you've doing and are willing
to moniter things a little more closely.

Sorry, I know this is a long post and probably some will be tempted to say
give it 4 years and you'll get you 'fish sense'. I'm hoping I can cut down
that time with some of your wisdom.
Thanxx
Bill Brister - Austin, Texas