Aquarium filtration and nuisance algae removal using a scrubber has been discussed at length on the Marine Fish UK forum. I didn't take too much convincing to read more about the process on Algae Scrubbers.net which made me feel confident enough to try one out on my 3'x 2'x 2' reef aquarium.
I have used 25mm pipe, super glue, cable ties and some 7 count plastic canvas (used in cross stitch) for my project. A slot was cut in the horizontal pipework, long enough for me to place the canvas in. The canvas was then secured by plastic cable ties. A basic "L" type design, it was fitted to my aquarium on the 9th January 2011.
As you can see, water was fed from a Maxijet 1200 powerhead, via a flexi pipe to the scrubber head. Lighting was initially provided on one side of the screen by a 11w cfl (energy effieicent) bulb, equivalent to 60w standard incandescent bulb. This was clipped to the side of the sump by some cheap clamps bought off eBay.
So, after 1 week, the screen was looking like this:
Having read more on the algae scrubber forum, I decided to increase the lighting to both sides of the screen, and increase the bulb size. I also used some tin foil on the uprights of the cabinet to reflect lost light back towards the screen. The bulb size became a 20w cfl (80w equivalent) on both sides. Results from week 2 below:
Over the subsequent weeks, the algae on my scrubber began to grow quicker and greener as nutrients were being used up (see below). I upgraded the Maxijet 1200 to a 3000lph pump, the greater the flow of water the better the filtration properties apparently. I had already turned off my skimmer to prevent items that could be utilised as food for my corals being removed from the system, but I was now about to remove the JBL BioNitratex from the sump. Until now, nitrates had been held at a steady 5ppm by 2 sachets in the sump.
It was mentioned to me that my algae scrubber wasn't receiving the greatest amount of light due to my lack of light reflection. I was pointed to a great article on how to make some cheap reflectors out of beer cans, so I begrudgingly sacrificed 2 cans in my attempt:
With the increased light and flow, my algae scrubber was able to remove more "muck" from the tank. The problem is that the screen was now becoming slimey and dark green, almost black. This meant regular cleanings (every 2 to 3 days) to remove the slime algae. It was explained to me that nutrients are stored in the live rock. As the nutrients become less in the water column, they leach from the rocks causing this type of algae. I am removing about 60 grammes of this algae from my screen on a bi- weekly basis, so hopefully the nutrient levels will drop soon enough to allow the "real green" algae to show through and filter correctly.
Luckily (for me), a fellow reefer on one of the forums I frequent was breaking his tank down. I was able to have "first dibs" on his algae scrubber, which again was a DIY effort, but much better than mine. My parameters before swapping to the new algae scrubbing unit were: Nitrite 0ppm, Nitrate 5ppm and Phosphate at 0.