[gpodio]

I'd say it's a pretty simple case of not having fast enough plant growth to saturate the water before the lights go out. Light and CO2 are both on the low side to saturate such a tank. The type of plants you have, slow Vs fast growers, will also contribute to this.

If your plants look good however I wouldn't consider the fact that they are not pearling a negative thing. Increasing lighting and CO2 will speed things up and force you to review most of your fertilization schedule. It's a high price to pay just to get a few bubble at the end of the day...

Giancarlo

 

[gpodio]

I don't quite understand the saturation and slow-fast part.

It's quite simple, plants prdoduce oxygen. This oxygen is dissolved into the water up to a certain point, when the water is saturate with oxygen, no more oxygen can be dissolved into it and so further oxygen produced by the plants has nowhere to go and forms the bubbles you are asking about. There are several considerations that contribute to the tanks' oxygen content, mostly the amount and speed at which plants are growing and the amount of gas exchange occurring in the tank. The faster the plants grow the more oxygen they create and the more likely it is that your tank will become saturated by the end of the day. Many tanks however don't reach saturation because they don't have the required light intensity, plant mass, or plant types to reach this point before the lights go out.

So as stated before, if your plants are doing well and you are happy with the tank setup I wouldn't change a thing. If on the other hand you want to turn your tank into a "sports car", you'll need more light, CO2, ferts and perhaps more plants or fast growing plant species that will contribute more to oxygen production compared to slower growing plants. My 55g with 275W of light on it for example barely pearls by end of day because more than half of the tank is planted with crypts, ferns and anubias which are all slow growers.

Hope that helps
Giancarlo Podio