My first scrubber!

[Floyd R Turbo]

That lamp is nuts man.

I think one thing with the 45W CFL is that with it being so close, the intensity might be too high to run is 18/6. If you're going to stick with a 12x12 screen, you're going to have a little bit of a difficult time lighting it evenly with only one lamp. Switching to 2 lamps of a slightly lower wattage might help.

I think based on your feeding schedule that you posted, you're probably more in line for 6 cubes/day. So I think the problem is two-fold, the light is too close/intense and your screen is oversized.

If you trimmed the screen down to 6" or maybe 8" wide and then tried to back off the lamps to about 1/2" from the reflector, and wrapped it to fit the screen, you would probably get better results. Also you would probably be able to cut down the light hours. I would say 14 on max, but until you start getting green growth, I wouldn't mess with that [i[too[/i] much. What you want is green but if you get yellow rubbery growth, then start knocking the photoperiod down 1 hour per week until you get a consistent green growth. If you get brown slime on top of green, then you're really close, just a bit too much light still. At least that the trend I am starting to notice.

[steve]

Update:

The scrubber did well and brought nitrates down to 5-10ppm and there was virtually no trace of hair algae although I never got the green hair algae to grow on the screen.

Then, in pursuit of perfection and in response to adding a new fis I did the following around 6th July:

Downgraded the screen from 12 x 12 to 8 x 12 as suggested
Lights were 3 months old so replaced them like for like at 2 x 45w 2700k cfl
Introduced copperband butterfly and increased food to tank (on top of what I was feeding already) between 0.5 to 1 cube per day to try and entice him to eat

During this time the nitrates have increased to 25ppm. So this weekend (19th august) I did the following:

Added 2 x 20w cfl to each side (ie 4 bulbs). The colour looks the same as the 45w 2700k but I'm not 100% sure. These are about 2"-3" from the screen
Reduced lighting time down to 9 hours as I'm now at 85w each side
Increased flow rate to just about the recommended 60lph per cm of screen width

I've added pictures to show the current state of the screen. Problem is tht when I did the changes at the weekend I did not need to clean the screen, so didn't. So what you see is the result of 2 days of growth based on new parameters. Is this a waiting game or do you suggest anything else. I'm actually a bit panicy as my copperband still isnt feeding and nitrates continue to increase!

[Floyd R Turbo]

1) what else is growing in the sump? Looks like marine plants and a later of chunks of algae

2) Is that a single reflector behind those 2 lamps?

3) in the third pic, are the lamps moved to take the pic, or is that how they are always positioned?

[steve]

1) its chaeto and caulerpa - I've just thinned these out after taking the photo (probably by one third).
2) there are 2 reflectors, one behind each bank of 3 light bulbs.
3) The 2 lamps aren't moved (I didn;t want them to close to burn the screen), however what is removed is the 45w cfl which sits in the middle and also the reflector which this is mounted on. I then put a piece of reflective carbaord along the side to reflect lost light coming out of the side. Once these are positioned there is very little seepage.

The second photo gives you an ieda of what it looks like with just the end reflector missing but with all bulbs and main reflectors in position.

I've also just removed the acrivated carbon and rowaphos!

[mess7777]

Your copperband can handle the nitrates, fish generally aren't affected by lowish nitrates. This is more of a concern for corals. That said, I have read a lot about copperbands being finicky eaters and a lot of people not having great success.

[steve]

Your copperband can handle the nitrates, fish generally aren't affected by lowish nitrates. This is more of a concern for corals. That said, I have read a lot about copperbands being finicky eaters and a lot of people not having great success.

I'm not sure the reasonably high level is helping to stimulate him to feed, but agreed its the corals and shrimps I'm more worried about, especially since these have only been in about 6 weeks after previously had to remove them due to the rocks being fully carpeted with hair algae. Its just a shame that we're not allowed to have the californian blackworms in the UK as this is almost certain to get him feeding according to a number of American reef sites.

[Floyd R Turbo]

I don't know if copperbands are sensitive to N but most fish can tolerate the levels you are at rather easily.

As for your setup, the rowaphos was likely pulling down P, and if it was at zero, this might inhibit growth and N uptake. it is a likely culprit. Your chaeto and caulerpa are competing as well.

Your lamps are strong, but not individually reflected, and your reflector needs to be moved closer to the lamp and screen. Same bend radius, just make it come as close as it can to the lamp and then the ends of it should almost touch the screen. With it that far away, you're losing a lot of light, and the bend of the reflector cannot match the light profile or it will reflect the light back onto the lamp. you want a parabolic reflector close to the source. hard to describe in words.

[Floyd R Turbo]

Ok quick paint sketch showing this. Doesn't include the 2 additional lamps which I don't think you need if you do this and remove the other macros.

Left pic is what you have

Right pic is what you want

[SantaMonica]

Macro's need to go.

[steve]

Macro's need to go.

Ok! I may need to do this over a week or 2 as I don't know much nitrate these are already pulling out and hence don't want a sudden spike.

Give the recent changes I made, when would you expect to start to see green, before I start playing with set-up again?

Floyd - not sure I understand the drawing. There is about 2" from lamps to screen and the lamps to the reflctors is between 3" and 5" depending on bulb/reflector position. Given I'm using 3 bulbs on each side, won't one reflecor give more light spread and limit the chance of burning rather than focussing the light on a specifi carea of the screen?