Bubbling

[HantuAir]

Hi, I have a tank in school ... was about 2 mths old. This morning, I saw bubbles coming out of the plants. There is an inconsistent supply of CO2 (due to manual regulator) and lack regular supply of liquid fert. This particular area is located at the end opposite of the reactor outlet. I noticed the following :
1) Shaded area, there's no pearling.
2) Area where there is strong water movement (co2 reactor output), there is no pearling.
3) Water changes approx once a week. Last change on Sat.
4) There is a bit of algae present.
My question is, is photosynthesis (the bubbling I guess) more reliant on good lighting rather than good fertilizer routine or co2? My 4 ft at home has got no pearling effect. My pl (4x36w) is the same as those in sch, but the bulbs are older, possibly less intense?
Is an all over balance (fert, co2, ph, kh, lights) required for proper photosynthesis to take place? I tried searching, but the search tool has gone kaphoot![] Pls help, Mahagurus!

[hwchoy]

well, no photo how to synthesis right? so where there is shade the stomata of those plants will be producing very little O2 so there would be little or no pearling even if the water is supersaturated with O2.

[naturetan]

From what I observed from own tank and others:

1) low lighting will reduce bubbling, even to no bubbling. For your case, 4X36W is consider low lighting.
2) high lighting but low nutrients, also reduce bubbling.
3) high lighting and good nutrients, bubble like crazy.

Exactly what nutrients too low to cause no bubbling at high lighting, not sure, but CO2 is definitely one of them. Suspect K too.

Whatever, it's better to keep a tank with healthy growing plants, then one that is bubbling but has poor growth/algae. Keep that light level if the plants are doing great. It'll require less maintenance.

[geoffrey]

IMO, light is the only factor that triggers bubbling BUT it is NOT the only factor in sustainable photosynthesis. Bubbling is but one part of the photosynthetic process in which electrons dislodged by photons are replaced by the H in H2O, liberating O2. Without supplementing CO2 and nutrients while increasing light will trigger initial pearling only in the beginning before stopping and gradually leading the plants to its death.

Furthermore, light regulates the opening and closing of the stomata via guard-cells surrounding the opening to facilitates gas exchange. When there is no light, the stomata closes because the net benefit from gas exchange is far lesser than the net loss of water through transpiration (except CAM). Hence, no liberation of O2.

That is why, IMO, most gurus do not advocate pearling as an indicator for plant's health.

[HantuAir]

Bros,thanks a lot. I definitely agree that pearling is not an indicator of healthy plants, that's the bottomline. But its just irresistable seeing them : ) Comparing the plants at school & home, my chaps at home growing much better tho. Thanks again. []