Need Advice with T5HO

[captblitz]

My Tank:

Size: 48" X 24" X 18"(ht). arnd 80 Gals.
Lighting: 6 bulbs T5HO in 2 aquasonic fixtures (4 + 2) which is as good as having no reflector. 4 Bulbs run most of the time. 8" from the water surface.
Substrate : ADA AS covered with River Gravel in most areas. only AS in the foreground.
Fertilizer: EI dosing.60-80gal
Filter: Eheim Pro 3 2075, Aquaball internal filter+ Koralia 1050 GPH circulation fan.
Co2 : Pressurised and injected through a ISTA MAX Reactor. Drop Checker Always kept yellow green.

Ok so i have these T5HO fixtures with 6 X 54 bulbs over my tank i bought them because i need the spread as i cannot raise them. The Co2 is kept some what stable and the drop checker becomes yellow green around 2hrs after lights on but i have noticed all my plants pearling only when all the 6 bulbs are on. With 2 bulbs on in the fore ground, only 1 lily near the Filter spray bar pearls. With only the background lights on i get no pearling. Why could this be?

After reading this forums posts i had a feeling that i have too much lighting. But i dont understand if its too much then why does the pearling stop when half the lights are off.

 

[dutchy]

Hi,

Pearling is not realated with plant health and growth, it is merely a byproduct of light intenstity and oxygen saturation of the water. You can have very good health and growth with no pearling at all.

4 tubes is ok, 6 is overkill. What you're seeing is the effect of less spread when just 2 bulbs are on. PAR reduces @ 10 micromols for every 4 inch of water column. With only 2 bulbs the distance to the less lighted part of the tank is higher, the plants produce less O2.

Just if you see growth deficiencies or stretching you should use more light, but the plants you're using don't need that much.

 

[captblitz]

Hi Dutchy,

Thanx for the info. I will try going down to 4 Tubes and see what effect it has.

I ran 4 tubes for sometime as 2 had stopped working and i noticed the Ludwigia Arcuata and repens was less red and the uppermost leaves were getting twisted. Is that because they were adjusting to the lower intensity of lights or were suffering from a light deficiency?

 

[dutchy]

Both, they try to adjust but if light is low, colouration is less. The plant might still be healthy under low light until the leaves fall off.