Am I doing this correctly? Pic's included.

[scubayachts]

Hello everybody,
I just started my scrubber three days ago and I am having some concerns. I currently have a 90 gallon display tank and a 20 gal sump where the scrubber is in.
Here are my current specs:
-A light on each side
-One side has a large reflector with a 43 watt CFL.
-Other side has the smaller reflector with a 23 watt CFL.
- 10"w and 13"h
The reason I have two different sizes is because I cannot use a big reflector on the one side because the front doors wont close. Both of the bulbs are very close to the screen (see pics and video)
I cannot cut the screen shorter because I would have to fill my sump up alot, but I can cut it width wise.

Some concerns:
-I am running the light 18hrs on 6 off. Is this right? Looks like I am getting growth on the outsides of the screen but nothing growing on the part where the light is directly pointed on. (see pics)
-Do I have enough flow? (see video)

I cannot back the light up on either side because of room under the stand. Should I cut down on the time? What are you opinions?

Thank you!

http://i701.photobucket.com/albums/ww11/scubayachts/Scrubber1.jpg
http://i701.photobucket.com/albums/ww11/scubayachts/Scrubber2.jpg
http://i701.photobucket.com/albums/ww11/scubayachts/scrubber3.jpg
http://i701.photobucket.com/albums/ww11/scubayachts/th_ScrubberVideo.jpg (http://s701.photobucket.com/albums/ww11/scubayachts/?action=view&current=ScrubberVideo.mp4)

[jimrawr1]

Im not expert but my screen gets burned and the lights are much further away than yours, so I would say you need to back them up about 4 inches or so

[Ace25]

I agree on 1/2 of it.. the 23w is fine at that distance, the 43w on the other hand I feel is much too close, although I see the reason why, it is due to space constraints on your sump. I would just replace the 43w with a 23w on that side and be done with it. I run 2x 42w CFLs on my second scrubber and they are about 4-5" away (but my ATS is facing the opposite direction so I can clip the lights on the ends of the sump instead of the sides like your doing) and on a 12/12 light schedule (18/6 proved to be too much light on mine).

[scubayachts]

Ok so I am going to switch out the 43 watt for the 23. What kind of hours at this distance should I run the lights?

[reefdiy]

What kind of hours at this distance should I run the lights?

According to the new guidelines for screen size and light:


New Scrubber Sizing Guideline (Sept 2011)

Scrubbers will now be sized according to feeding. Nutrients "in" (feeding) must equal nutrients "out" (scrubber growth), no matter how many gallons you have. So...

An example VERTICAL waterfall screen size is 3 X 4 inches = 12 square inches of screen (7.5 X 10 cm = 75 sq cm) with a total of 12 real watts (not equivalent) of fluorescent light for 18 hours a day. If all 12 watts are on one side, it is a 1-sided screen. If 6 watts are on each side, it is a 2-sided screen, but the total is still 12 watts for 18 hours a day. This screen size and wattage should be able to handle the following amounts of daily feeding:

1 frozen cube per day (2-sided screen), or
1/2 frozen cube per day (1-sided screen), or
10 pinches of flake food per day (2-sided screen), or
5 pinches of flake food per day (1-sided screen), or
10 square inches (60 sq cm) of nori per day (2-sided screen), or
5 square inches (30 sq cm) of nori per day (1-sided screen), or
0.1 dry ounce (2.8 grams) of pellet food per day (2-sided screen), or
0.05 dry ounce (1.4 grams) of pellet food per day (1-sided screen)

High-wattage technique: Double the wattage, and cut the hours in half (to 9 per day). This will get brown screens to grow green much faster. Thus the example above would be 12 watts on each side, for a total of 24 watts, but for only 9 hours per day. If growth starts to turn YELLOW, then increase the flow, or add iron, or reduce the number of hours. And since the bulbs are operating for 9 hours instead of 18, they will last 6 months instead of 3 months.

This is based on feeding, not water volume. Not sure what you are feeding but hopefully the following is helpful in pointing you in the right direction.

You are running 130 sq.in screen which according to the old guideline (and this one as well, if you do the math) means that you need 130Watts of light if you wanted to run it 18 hours a day (1W per sq.in) or 260Watts of light if you want to run it for 9 hours a day (2W per sq.in). (This is based on 12Watts for 12 sq.in for 18 hours - as seen above)

This is obviously ridiculous!! So from where I am sitting and from what I have learned I would say you could reduce your screen size considerably and run it at 9 hours a day with the two bulbs totally 46watts. By the same math/reasoning you should be able to reduce your screen size to 24 sq.in (ie. 6" x 4") and then run the lights for 9 hours giving you power savings and increased growth/filtering. Make sure that with your reduction in screen size that you have approx. 35GPH per inch of slot length flowing over the screen. (ie. 6 inch slot = 210GPH coming out of the pipe from overflow or pump. This gives you 35GPH per inch).

Also should be noted that reducing the hours will reducing the burning in the middle of the screen. The only other option is to move the lights further back. You might be able to re-orientate the screen if you make it less wide so that the lights can click on the ends of the tank and be further away.

All of this is just and opinion/idea.....except the math....that is just how the numbers are crunched.

I would read this (extremely helpful): http://algaescrubber.net/forums/showthread.php?1291-Algae-Scrubber-Basics-The-Summary

also:


Double watts = double feeding
Double area = no more feeding
As long as the screen is catching ALL the light, then increasing area will only reduce filtering because it spreads the growth out too thin and it does not get a chance to grow out and into the light and flow.

[Floyd R Turbo]

In addition I would replace the large reflector with the smaller one and go 23W. Alternatively, you can take advantage of the new sizing guidelines and use the CFL floodlight lamp and make your screen 6" wide, and just light up the part about 1" down from the pipe, and let the additional length of the screen down to the water remain unlit and not contributing to filtration. Basically just a 6x6 screen (with the CFL floods, knocks it down a bit, so 2+ cubes/day filtering capacity) with a non-filtering extension. That would solve your space problem and your growth problems. Lights on 18/6 until your screen is cured up, knock it back to 14 on if you still have burning, then knock down 2 hours per week if you are still getting burning, but that should not be a concern as you will be able to put the lights further away from the screen not having to deal with the reflectors (just take them off and use the sockets you have)