New Scrubber: Am I Ok with 6500k Bulbs???

[jcommerce]

Howdy Folks,

I've been lurking around this site as I've been plotting and scheming to build my own algal scrubber for my 120 gallon reef tank. Well, two days ago I decided to go for it and I've attached some pics for you to check out. It is a siphon system utilizing an 18 gallon rubbermaid storage bin. The siphoned water runs through vinyl tubing and into a PVC pie which is attached to the bottom side of the bin's lid with zip ties. I used a Dremel tool to cut a 1/4" slot in the PVC and used a plastic needlepoint sheet (bought a set at Wal-Mart for $1.97) for the algae sheet. I used small clipped off zip ties at the top of the sheet to suspend it from the PVC and the end cap is removable which allows me to pull the PVC out and take the lid off for easy cleaning. The water is retured to the sump via a bulkhead fitting near the bottom of the bin and additional vinly tubing with a couple of PVC elbows. 23 Watt Daylight 6500k outdoor compact flourescent bulbs are mounted on either side of the bin and are spaced about 4 - 5 inches from the screen. I drilled holes just slighty wider than the light sockets and used a glue gun to secure the bulbs at the widening of the built in ballast each bulb has (I think it's a ballast???). I tested the bulbs to see how hot they got before I did this as I feared that they would heat up and melt the glue, but these bulbs run cool enough that the glue stays hard. It's not how I preferred to mount the bulbs and I was thinking to myself that it probably won't be too fun changing the bulbs when they burn out. But now I'm thinking I might be taking them out sooner than I thought (see below)

It all seems to be running quite well and I've seeded the screen (not sure this is effective) with some algae from my tank overflows. However, I'm now questioning whether or not the 6500k bulbs will grow the necessary algae or if I will need to switch to 2700k bulbs. I've seen pictures and have read posts of people having success with 6500k daylight bulbs, but it seems like the consensus is to go with the lower, red/orange spectrum bulbs. However, I REALLY don't want to get the utility knife out and start cutting my 6500k's out just yet (plus they don't have the outdoor 23 watt 2700k bulbs at my Home Depot either).

Will my scrubber be functional with these 6500k bulbs? If I have to make the change, I was thinking of changing one to 2700k and leaving on at 6500k just to see the comparison. But my main goal is to clean up my water so I can start getting into SPS corals and really have the tank I've wanted for a long time. But I want to get all my water parameters perfcet before I start emptying my wallet. Let me know your thoughts. Thanks!

[jcommerce]

More Pics.....

[SantaMonica]

6500 will be fine for now. In 3 months replace with 3000. Better yet, put two bulbs on each side for even stronger filtering. A 120g tank can use 120 watts for strong filtering.

1/4 inch is a bit wide for a single screen. 1/8 inch is better. Or 3/8 for two-layer screens. Make sure your screen is super rough, and consider making it two-layered.

[jcommerce]

I am happy to say that, upon further inspection, I now have algae growth starting on my screen after 48 hours of operation! The screen is turning a darker color and looking closely, you can see the small brown and green fibers of the growth just beginning.

Regarding the width of the slit on the PVC, I started out very thin and did a couple of test runs. Due to the thickness of the screen, I was forced to widen the slit a couple of times until the water flow was even and unrestrained across the entire screen. On my first test, there was sporading, strained flow across the PVC and there was a lot of overspray. I was concerned about clogging of debris fromt the siphon and/or algae growth. Now there is a uniform, even flow of water cascading down the entire screen.

On a sour note, I found this morning that one of the bulbs is already out. Even though the socket is not exposed within the box (it is outide of the box), there is a small seam between the glass bulb and the ballast which I believe was exposed to saltwater mist/spray and somehow corroded the interior connections. This time, I will fill the seam with a thin layer of silicone as well as on the stilll functioning bulb. I guess the good news is that I'll be able to replace that bulb with a 23 watt 2700k bulb and I'll be able to do the comparison between bulbs. The bad news is that I get to have the fun job of using the utility knife to cut the old bulb out (I was hoping I wouldn't have to do that for at least a year and a half). That glue gun glue is amazingly strong!

I think I'll just stick with the combined 56 watts for now and see how it goes. It's almost too bright to look into the box as is and there is new algae growth across the entire screen. I can always look at adding more down the line.....

[jcommerce]

Well, it wasn't too painful changing the bulb out. That glue is strong, but I was essentially able to pry it out. I now have a 23 watt 6500k bulb on one side and a 23 watt 3500k bulb on the other....an unintended little experiment going on here to see if there's any significant difference in algae production. I sealed the small seam between the glass bulb and ballast on each bulb, so hopefully I won't run into that corrosion short out problem again. I'm now seeing a lot of color on the screen in just 72 hours of operation.

[ChrisD]

Hi. If you haven;t already, just make sure that you plug those lights into a circuit breaker - it's amazing how salt creep gets around. I had a similar experience and it tripped out the circuit (I am lucky that all the house circuits are protected by and RCD at the consumer unit).

Also, make sure you don't block any intended ventilation. As you know these lamps and ballast get hot. Reduced ventilation would definitely shorten life and I guess at worst cause a fire.

good luck with the screen and stay safe :geek:

[kcress]

A GFI outlet would be better. ..

[jcommerce]

I agree with both of you.....I think I should be good to go. The outlet is GFI and luckily, the bulbs are running quite cool. By dumb luck, the unit is actually sort of self ventiliating, oddly enough. The drain line is pulling air through as the water is flowing out and and since I cut ventilation holes at the opposite, upper end, it's causing air to be drawn in and across the screen and bulbs. We're not talking a ton of air, but enough to keep things from getting too hot and damp. However, there is still some condensation on the inner walls though of the bin.

Also, I think I should be good this time since I added the silicone around the seam between the glass bulb and ballast and they are the outdoor type bulbs. Along with the glue, it should be nearly impossible for salt to escape and get to the sockets on the outside. Guess only time will tell....

The screens are rapidly turning a brownish color with new algae growth. Also, I'd have to say that the 3500k side is looking like it's in the lead over the 6500k side.

[jcommerce]

Here's a video update on my scrubber at about 2 1/2 weeks running. I moved it from the spot next to my tank to behind the wall, behind the display, along with a new refugium.

http://www.youtube.com/watch?v=ESsDbHsxpjQ

[kcress]

WOW, a video with clear pleasant commentary. How novel!! (I hate the music and the mutes.)

Why all the venting on your scrubber?

[jcommerce]

Thanks, I thought some commentary might be informative....but maybe I'll play a little reggae on my next one ;)

The vents were 2 fold, to get some ventilation in there (some people hook up pc fans, etc)...it would get really hot in there otherwise, and so I could easily check the growth and to see what's going on in there.

[ReefMe]

Nice work!

[jcommerce]

Thanks ReefMe, here's some vid of some pods and chaeto in the new fuge....lots of pods in the scrubber too. My scrubber's new algae is mostly brown, hoping I'll see more green before too long.

http://www.youtube.com/watch?v=Sds-eOKWcWc

[jcommerce]

Srubber at approx. 7 weeks:

I'm happy to say that I hit undetectable nitrate levels over the weekend with my fuge/scrubber combo setup as seen in the video above. Started in the 40 - 50 range, then fell to 30s for a couple of weeks, then 20s.....then over the course of a week over Xmas/New Years, the levels plummeted to around 2. A few days later, they're undetectable.

It's hard for me to say whether it's predominately the scrubber or the fuge doing most of the work. I'm harvesting a good amount of algae from the scrubber weekly and the chaeto in my fuge is growing very rapidly. I think they're both working well. I wish the brown, slime algae would disappear from my scrubber. I'm seeing more and more green, but the brown keeps coming albeit a little less every week it seems.

[SantaMonica]

Great to hear. Once the levels start falling, the green grows better. And green has more surface area to do more filtering, so the levels go down even faster then.