DIY LED ATS - no growth

[Surykor]

Hello RC,

I have built a waterfall ATS to fix my ongoing nutrient issue. But It seems it can't grow algae at all for some reason. I have it up and running for more than 3 weeks now without any success.
All I can get is very lightly brown colored slime wich I rinse every week with tapwater. Click on image for full resolution for better idea.


spec as following:
roughed screen size- 5,1x5,1" (plastic canvas I use has only 4 squares per inch but I dont see this as a big issue, or?? )
on bottom of pic there is unroughed area of screen so water can enter sump on screen rather than free falling.(although spashing noise is present anyway)

Flow- 317gph pump, actual measured value is 37gph per horizontal inch.

Light- Grow LED 12W total 40LED -34red /4 blue/2 warm white.
running 1 per side 9hours a day. 3,5" away from screen.
https://www.amazon.com/ACKE-Lights-Spectrum-Growing-Hydropoincs/dp/B01LX1EO3W/ref=cm_cr_arp_d_product_top?ie=UTF8

No3 - 10ppm
Po4 - 0,008ppm (hanna ULR)
I have a lot of GHA and some green cyano in display so my params are false reading to some degree.

All I can get is lightly brown colored slime wich I rinse every week with tapwater.

Thank you for your time and advice.
Sury

 

[Sharpimage]

Mine took 3 to 4 weeks to start growing. I would stop rinsing it and let it go for a bit

 

[hersheyb]

Increase the light schedule I would start off with 16 hours and see how it goes and adjust as needed.

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[journeyman]

Increase the light schedule I would start off with 16 hours and see how it goes and adjust as needed.

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This. Your tank lights are out competing your ats. You can even go 24 hours to go y your ats a head start.

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[Surykor]

Thanks for your replys.

I decided to start on lower photoperiod to prevent photosaturation on new screen, it seems I chosen opposite approach as you advice :-D .

I will double the photoperiod to 20h and will see after one week.

 

[SantaMonica]

7-count screen would work better, more plastic to attach too, but use what you have now since it is done.

 

[laverda]

Like others have said more light and stop rinsing in fresh water. You might consider turning off your display lights for a few days as well.