New Scrubber - No Green Algae

[Garf]

If you follow the recommended figures, you could get rid of 50% of your screen. Instead of cutting your screen, I would be tempted to try an oversized slot shading thingy as described above. Ie shade 2 inches of the screen from the slot pipe down, this can then be altered whenever you need to increase feeding. However, cutting the screen would be the tried and tested method.

[Floyd R Turbo]

Just a point, you do have green algae growth, I can see it in one of the pics. It's covered up by a slime layer. I get that too. Filtering is still pretty effective on mine even with that. I was running a shortened photoperiod, I bumped it back higher and my dark slime has dropped off a bit. Intensity is key.

[regmo123]

Thanks Floyd.

Sorry for the dumb question, but what do you advise to increase intensity on my setup?

[Floyd R Turbo]

can you bump the T5s to T5HO or are they already HO? Pics of the entire setup would help. Total lighting wattage is only one piece of the puzzle.

[tomservo]

I don't think there is such a thing as 12" T5HO, Floyd. He might be able to overdrive them with the right ballast, but adding reflectors if he doesn't have any would be a good option as well, if there's room.

I thought it was 1w per sq in per side?

[regmo123]

Floyd - I don't think I can get T5HO in 12" length (if you know where I could get them then let me know ).

I've added some pics - hope they help, if not let me know what would helpful to see and I'll take the right pics. These show the screen in operation and the general positioning and inlet to the ATS.

Tomservo - I've got reflectors behind the T5 tubes. They're 8W 3000k rating - any views on the lumen rating (is this correct for the ATS?)

[Garf]

I don't think there is such a thing as 12" T5HO, Floyd. He might be able to overdrive them with the right ballast, but adding reflectors if he doesn't have any would be a good option as well, if there's room.

I thought it was 1w per sq in per side?

No, it's 1 watt per inch of screen whether 1 sided or 2 sided and that's why 2 sided is more effective I believe. You can do I watt per inch per side and half the photoperiod on 2 sided screens.

Regmo123 - how long are your scrubber lights on for?

[Floyd R Turbo]

Ok I was wanting to see if your reflectors and the rest of your setup were good. Looks good to me. It's not necessary to go HO but it helps increase light density if you can, otherwise you have to cram more lamps in the same area and use smaller reflectors - and you start approaching the point of diminishing returns.

3000K is right

You don't want to go double-lit and half the photoperiod on a single sided screen - can't use that 'rule'. Single sided is weak to begin with, you need the full photoperiod IMO.

The design guideline is 1W per dimensional sq in of screen, split between both sides. So 60 sq in = 30W per side. You're a little low, and one thing to consider that I have found is that in the center of the screen, the screen is getting light from all angles. Near the ends of the lamps, there is a sharp intensity drop-off and the screen is only getting about half the light. I trimmed my screen down so that the length is 1" shorter than the actual glass part of the lamp on both ends. I was only getting darker red turf in that area anyways, which grows better in lower light apparently, and after cutting that area out it did not return. So I would consider shortening your screen. This mean of course cutting a new slot tube, but it will also increase your flow rate per unit length of screen

[Garf]

I have been looking at a UK reefing site and I think I have found the place you bought your scrubber from. Have been looking at other examples and they all seem to be suffering from low flow problems. Your pump is 2000lts/hr but probably not delivering that to your screen with head loss etc. Other people with identical units are growing algae into the slot further reducing flow. The lighting units are only delivering 1100 to 1200 lumens per side, this also seems low ( 2 x 20watt cfls can deliver 2200 lumens ). JUST FOOD FOR THOUGHT.

[regmo123]

Thanks Garf - interesting stuff.

Based on your review of the unit, what's your view of the changes I could/should make to boost algae growth? I don't really want to change the lighting units as they fit well into the ATS housing. I've just changed bulbs (previously 3500k, now 3000k) but not sure of lumen value (I'm guessing probably 400 lumens per tube) - how can I work that out?

I did see somewhere else on the forum that plant growth T5's are recommended but I'm not sure if the kelvin rating will be too high (eg Gro-Lux 8w). Views?

Thanks