How much light?

[kty]

Hi there. I have a 140ltr tropical tank and I'm having trouble with my plants. I was recently advised on here that my lighting was wrong. I have since bought a strip light that said was for fish and plants. It is a 30" interpet daylight bulb. I think it's 25w (that bit has worn off a bit ) since switching to this light my plants are doing worse. I have a pkanted substrate under the Gravel and I add a monthly nutrient liquid. And I give 2 boosts of co2 a day one in the morning and one at night. Any advice would be great. Xx

 

[Demeter32]

That lighting is less that 1 watt per gallon, which is very low. Adding fertilizers and the CO2 isn't helping the plants at all because the amount of nutrients they take in is directly dependent on the lighting. The less lighting there is the less nutrients the plants take in = slower growth. You probably have a big imbalance of dissolved nutrients in the tank which could lead to an algae problem. I would stop dosing the liquid fertilizers until you get a better light.

You should have at least double the amount of lighting you have right now for a low light tank. Your tank is about 36gals so it will probably be easier to buy a good LED lighting system for planted tanks or find another DIY way, such as LED flood lights.

 

[Byron]

Can you provide any more data on the light, or a link to some? I tried to find it but Interpet make so many different lighting units.

I am assuming this is a T8 fluorescent tube, one over the tank, correct? I did find a fluorescent tube, T8, named "Tropical Daylight," that had a colour temperature of 15000K. If this is what you have, this is not going to work, as there is so little red in this colour temp and red is the prime driver of photosynthesis.

Also, what is the tank size (dimensions especially)? And what plants are you attempting to grow?

Last question, what is the liquid fertilizer you are using?

Is the CO2 diffused CO2 or a liquid carbon supplement? I would stop this, it is not going to do anything without good light and the other nutrients, and I would suspect light to be the main thing. A different tube will fix that, I can suggest some once I have the data.

Byron.

 

[Byron]

Demeter32 posted simultaneously with me...

We might be able to do this with what you have, depending. I have a 36-inch 33g tank with one 30-inch T8 tube, and thriving plants. It all depends upon your light specs, and the plant species.

New lighting may in fact be necessary too, depending...we'll get you there either way.

Byron.