Would you say oxygen bubble production is NECESSARY to a successful plant tank?
 I have a fairly high-tech plant tank (no substrate heat, only diy co2 at the
moment) and no bubbles.  I have not changed any water in the last 40 days and
the tank is heavily stocked with fish which are heavily fed.  The fish are
doing great (the neons spawn almost daily) and the plants grow some, but no
bubbles and no great spurts of plant growth.  No need to thin (yet).  The tank
is about 6 months under its present management.  Am I being impatient or is
there some reason for concern?  Here are the nitty details:

1. What size tank do you have?   55_ US gallons or _____ liters
   How long has it been set up as described below?  6______ months
2. What dimensions?  36 inches   length (large horizontal dim.)
                         15 inches  width  (small horizontal dim.)
                         20 inches   height (vertical dim.)

3. What substrate (gravel, sand, or ???)? #3 aquarium
4. What particle size? 2_____ mm x 4______ mm
5. What filtration do you provide?  (Include model numbers if possible):
    ugf with 50gph powerhead

6. What kind of lights do you have over your tank? (Include type, brand
    and model, wattage, age)      
    30w Triton, 30w cool white, 20w aquarilux
7. What is your lighting schedule?  10 h off, 4 on, 6 off, 4 on
8. How many and what size fish do you have in your  tank?  too many.  3":
   2 angels, 2 rainbows, 2 pearl gouramis, 1 loricaria, 1 farlowella (close to
   9"); 2.5": 4 congo tetras, 1 boring gourami, 1 paradise fish;
   2":  1 betta, 1 oto; 1"+:  18 neons and cardinals.
   When did you last add fish?  What fish?  1 month ago, farlowella
   How many and what size plants do you have in your tank? 2 large swords,     

   many stem plants (bacopa, hygrophila poly., maybe 9 stems all told), 
   3 anubias, 12 crypts, 5 aponogetons, 3 java fern, 5 dwarf swords.

9. Would you say you feed fish lightly or heavily? very heavily
10. What kind of food? color flake

11. Do you add (inject) CO2? yes

12. Do you add any fertilizers (describe as completely as possible if so)
   yes, chelated micronutrient mix added at water changes_________
    Do you add any water conditioners, medications, salt (describe)
    Do you have any driftwood, seashells or other decorations (describe)
    3 10" pieces of driftwood___________
    How often do you do water changes and how much water do you change?
    5-10% once or twice a month
    Anything you want to remark about the water you use for changes?
    tap water, very low tds

13. Please indicate test values for as many of the following water
constituents as you can (tell units used):

   pH (Hydrogen ion concentration, prefer AM and PM readings)  6.6/6.7
   KH (alkalinity)  3dH
   CO2 (Carbon Dioxide concentration)  15-20 ppm
   Ca (Calcium ion concentration)  low (I think)
   Fe (Iron, report as total Iron or Fe++ or Fe+++, tell which)
   N  (Total nitrogen or ammonia or nitrite or nitrate, tell which) 
        nitrate 25ppm or so
   PO4 (Phosphate concentration)
   K  (Potassium concentration)
   Cu (Copper concentration)
   any others you know

14. Now describe the symptoms or problems you are having:
   No bubbles, I don't HAVE TO prune/thin.

Dave Gomberg, Experimenta      San Francisco CA USA   gomberg at wcf_com