howdy from the uk - day one

[Garf]

2 x 23watt cfl's each side and on the thicker side an additional 15watt T8 blue(ish) tube for 18hours a day. Beginning to wonder if I should take the plunge and rig up an LED system to really boost the growth.

[Garf]

Not gonna get any more on the screen I reckon. Just about maxed out ! Started (only just) to degrade the lower levels at 9 and 18 days, nearly 400 grammes harvest and water looks great (skimmer in operation also bubbles on screen).


edge on 9days left, 18 right



9 day side



18 day side

[Garf]

I know SM has said before that increasing light has increased filtering potential, but finally I've found a paper that suggests the reason behind this, and it's got little to do with extra growth. In fact it's to do with supplying more light than the algae can use for growth.

"This indicates that with intense illumination, the CO2 fixation rate can exceed the rate of nitrogen assimilation and, thus, the excess carbon and energy derived from photosynthesis are stored in the form of glycogen (Fay, 1983; Campbell et al., 1998; Zak et al., 2001). "

This indicates to me that thick growth may be under illuminated in many instances. To this end I've ordered a 50watt UFO LED grow lamp, to illuminate through the harvested side of the screen, deep into the un harvested side.

Will keep you posted

[Garf]

Another update, still no die off at the screen. Appears I was wrong about it being maxed out. Got extra 15% harvest this time at 450 grammes wet weight......


Edge



9 day



18 day



Sticking with harvesting at 9 days for now.

[sabbath]

I know SM has said before that increasing light has increased filtering potential, but finally I've found a paper that suggests the reason behind this, and it's got little to do with extra growth. In fact it's to do with supplying more light than the algae can use for growth.

"This indicates that with intense illumination, the CO2 fixation rate can exceed the rate of nitrogen assimilation and, thus, the excess carbon and energy derived from photosynthesis are stored in the form of glycogen (Fay, 1983; Campbell et al., 1998; Zak et al., 2001). "

This indicates to me that thick growth may be under illuminated in many instances. To this end I've ordered a 50watt UFO LED grow lamp, to illuminate through the harvested side of the screen, deep into the un harvested side.

Will keep you posted

Wouldn't you want the brighter LEDs on the unharvested side? This would get the light down deeper into the thick side. If you put it on the harvested side. I would think that it could burn the thinner algae. Or is that what you meant?..

[Garf]

Wouldn't you want the brighter LEDs on the unharvested side? This would get the light down deeper into the thick side. If you put it on the harvested side. I would think that it could burn the thinner algae. Or is that what you meant?..

Gonna try it on the thinner side first to get right to the "inner layers" of the 9 day old stuff. But yeah, I agree there is a risk of over doing things, but I'll be reducing the distance between lights and screen incrementally, so hopefully the screen will become acclimatised over a few weeks. Because my scrubber is set up to view the unharvested side, hopefully this will allow me to see how much penetration is going on, through the algae, just by turning the cfl lights off.

[Garf]

Wouldn't you want the brighter LEDs on the unharvested side? This would get the light down deeper into the thick side. If you put it on the harvested side. I would think that it could burn the thinner algae. Or is that what you meant?..

Decided to put it on the unharvested side like you said, two reasons, first it was easier, second made more sense.

[Garf]

No pics today but 500gramme harvest, attachment to the screen is extremely firm.

[Garf]

Previous picture was an 18 day screen (grown with cfl's). Here's a pic of an 11day screen, 9 days under cfl's, 2 under the LED. Seems to be filling out. Nicely.

[Garf]

7 days exposure to the LED and all looks good;


Under LED



Under Flash only