why my plant not pearl any more? too much CO2? pls help.


New Member
2 Feb 2009
i just set up a new plant tank, auquasoil, high light , high CO2,

the tank is very small, only about 30L, but kinda tall, about 15 inch. the light is 3X24w, although part of tubes are outside the tank surface. i know the light is very high, thus normally only 2 tubes are on.

the CO2 is on 24 hours per day, i do not know exactaly how much, i guess about 3 bubble per second, as all the snail of tank are out for surface gasping for air :twisted: there is no fish yet, so i do not mind a little high CO2

the problem is, although the first 2 days plants pearling a lot. But now, none of them do it any more, even ricca. meanwhile, all the plants do look kinda sad, not much growth i can see.

the another problem is, there is a white film with some dirty bubbles on the water surface, as there is not much surface movement, i know it is kinda normal when you cycle tank, but i have never see so much, so thick disgusting film.

i guess some kind of nutrition of tank was used up, thus the plant not growing, maybe O2? as the thick film block the O2 exchange.

or marco?

or i should cut down to 1 tube of light?

do i need to change water more often? as i know aquasoil need a lot water change, but i used it b4, never had problem like this.

normally plants do well in new tanks, even no CO2 and low light, where the problem is?

Many thanks


Expert/Global Moderator
Staff member
11 Jul 2007
Chicago, USA
Well are you actually dosing nutrients in this tank, like say, Nitrogen, Phosphorous and Potassium (macros) or even traces?? Plants produce oxygen, you don't need to feed it to them but they'll only produce oxygen if you feed them the macros + traces.

On a small tank like that many people tend to use Tropica Plant Nutrition+ which is an all-in-one product. Cheapskates can learn to make a home brew version of this product here: JamesC's All In One Solution

Hard core fanatics can try reading EI DOSING USING DRY SALTS

And yes, you do have too much light so I'd consider shutting down at least one of thos bulbs and probably two otherwise you'll soon have an algae farm... :wideyed:



New Member
2 Feb 2009
i did not dose anything , but i will order some soon.

However, i had planted tanks b4, never dose, most of them grow very well.

This time nothing grow, plants are dying. i guess the problem might cause because the tank is not cycled.

i have not see green algae , those kinda green spot grow on tank glass when the light is high, but i do see some
hair algae, but the color is brown instead of green,even the algae look kinda unhealthy :rolleyes:


6 Jul 2007
Aston, Oxfordshire
The problem is mostly like a lack of nutrients. The lighting you have is forcing the plants to work ultra hard, but you're not providing them with the other essentials, in this case the fertilisers (you have the CO2 sorted). They probably pearled to start with as there was plenty of ferts in the water, but these have probably been used up now.

Until you get some ferts I would reduce the lighting to 1 bulb only, or you may find the plants burn themselves out and die.

Hope that helps :)

Thread starter Similar threads Forum Replies Date
Kezzab Does excess co2 inhibit plant growth? Carbon Dioxide (CO2) 38

Similar threads