New algae scrubber. Lighting questions.

[Tanked425]

I built my first algae scrubber 10 days ago. I have a 110g display tank with a 40g sump/refugium. The tank has been up and running for a year and a half now. My nitrates have always been around 20ppm. I think this is because of our snowflake eel as he produces a lot of waste. I thought I would try the ats and see how it goes. When I first put the scrubber in the nitrates were between 20-25ppm. After my first cleaning which I did at 7 days, the nitrates were at 10ppm. The screen at 7 days was a light brown color with some hints of green, I was running the lights for 18 hours a day. Now at 10 days the screen is very dark, almost black looking, the lights are being ran at 12 hours a day. I will be cleaning the screen today to remove the black algae, I will also be roughing up the screen a bit more. As of right now I have two lights, one cfl on each side. The bulbs are equal to 60 watts each. Is this enough for my screen? Im currently running the lights for 12 hours a day. The screen size is 6" x 8". The pictures show a larger screen, but that is when I still had to much hanging in the water. I was reading that the screen needs 1 actual watt per gallon. I found a few bulbs at home depot that are 42w (equal to 150w) and 2700k color temp. Is this to much light? I would like to run the lights between 8-12 hours a day, rather than 18 hours. Any help or suggestions would be great. Thanks!

[Floyd R Turbo]

Screen sizes are based on feeding now, 12 sq in for each cube of food fed per day on average. So check that first and you may want to adjust the screen size accordingly. 6x8=48 or 4 cubes/day, if it's set up right. I find that most people don't feed much more than 2 cubes/day, and you would only need a 4x6 screen for that.

Your lights are not pointed perpendicular to the screen, so you are losing a lot of efficiency. Looks like a crowded sump area so I guess you have to do what you can. But if you can downsize the screen to match feeding, you might be able to use CFL floodlights instead of dome reflectors.

The black algae indicates high nutrients, you want to clean all of this off immediately whenever you get it as it block light to the lower layers and results in detachment of algae if you wait too long. Once nutrients are reduced, it should turn brown then green, assuming the rest of the setup is right.

To utilize the double-light rule, which is what you are referring to when you wish to run less hours, you really need the screen to be "capturing" most or all of the light. That means reflectors pointed directly at the screen. If you went to a 4x6 screen (effective area, at least) then a 23W CFL floodlight would do pretty well, take up less space (no need for reflectors) and you should be able to run them less hours, once the nutrients are under control. It should also help push through the dark algae growth phase quicker.

As far as the screen goes, you really only need about 1 inch below the water to cut down on bubbles. So chop all the extra off, it's not doing you any good.

All in all, I would say leave the width as is and just put the CFL floodlights on. You would get a little growth outside of the spot, and that area probably would not grow green, but all you care about is the 'effective' area anyways. Saves you from cutting another slot tube.

For roughing up the screen, check this video of mine

[Tanked425]

First of all, thank you for the reply. I appreciate the help!

The screen size is a little large, I may make it smaller. But as of right now I do feed three cubes a day, and i also feed our eel every 3-4 days. So it may be slightly oversized but I will see how it does first.

The flood lights were a great idea, especially to save space. I put on two 23W cfl flood lights and have them mounted roughly 2-3 inches from the screen. Is this ok, or should I adjust them.

I have the lights scheduled for 16 hours on right now. What should they be at?

I also cleaned the screen, and I also roughed it up more today.

Here is a photo with the new lights! Thanks again for the help!

[Floyd R Turbo]

That looks much better. Leave the hours at 16 until nutrients drop and nuisance algae goes away. If you start getting yellow growth cut the hours back by 1 hour/day, if you get dark growth clean every 3 days (and leave the lights at 16)