Re: O2 Bubbles

> From: gomberg at wcf_com (Dave Gomberg)
> Date: Sun, 17 Sep 95 17:57:03 PDT
> Subject: Bubbles
> Would you say oxygen bubble production is NECESSARY to a success

It depends what you term "success".  If you want to balance a tank 
at a lower level, with slow-moderate growth, then you may very 
well not see O2 bubbles (although if you look carefully, you may 
see small bubbles forming underneath broad leaves) because, as 
others have said, if you do not exceed O2 saturation levels in the 
tank, you will not see bubbles.  My tanks with bright light run 
about 11 mg/l O2 by mid-day, and only drop to just under 
saturation (about 8 mg/l) by morning.  So I see bubbles within an 
hour or so of the lights being turned on.

My less bright tanks still run around 8 mg/l O2 during the day, 
but that's not enough to see bubbles.  

> 6. What kind of lights do you have over your tank? (Include type
>     and model, wattage, age) 30w Triton, 30w cool white, 20w >  
> 7. What is your lighting schedule?  10 h off, 4 on, 6 off, 4 on

I would consider your lighting low-moderate.  Not likely you'll 
see much bubbling from the plants at this level.  OTOH, if you 
increase the lighting, you also usually need to increase CO2 and 
trace element supplementation.  Why do you keep the photoperiod so 
short?  Even if you don't want to increase the wattage, you can at 
least keep the lights on 12-14 hours daily.

>    How many and what size plants do you have in your tank? 2 lar
>    many stem plants (bacopa, hygrophila poly., maybe 9 stems all
>    3 anubias, 12 crypts, 5 aponogetons, 3 java fern, 5 dwarf swo

As others have said, I'd increase the plant density substantially, 
emphasising fast growing stem plants in the beginning to use up 
excess nutrients.

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

>     How often do you do water changes and how much water do you 
>     5-10% once or twice a month

This is where you're going to have trouble if you try to go for 
faster growth/ O2 production.  When you increase the lighting, you 
are very likely to have algae problems with your heavy feeding, 
low water change schedule.  I'd reduce the feeding and increase 
water changes to 25-30% weekly.  

If you _do_ decide to increase lighting, _MAKE SURE_ you get the 
nitrate and phosphate levels _very_ low before you do, or you'll 
get algae along with bubbles.<g>


Karen Randall
Aquatic Gardener's Association