View Full Version : DIY vertical algae scrubber

10-06-2011, 01:04 AM
Hi all,

I built a vertical algae scrubber based on the one described by "SantaMonica" all over the Internet, and closely based on the the one detailed in the following thread. http://www.thescmas.com/forums/showthread.php?4464-Algae-Turf-Scrubber-amp-Frag-tank-build

As some of you know, I have a 60 gallon cube tank which, with the refugium and sump minus rock and sand, has about 75 total gallons. I elected to go with a 14"x5" screen and it has been putting out a respectable blob of algae each week.



It is lit by two 18" T5-HO "plant" lights with good reflectors (I bought one 36" reflector and cut it in half with tin snips), powered by a Fulham Workhorse 5 ballast. Although the wiring sheet for the ballast does not mention 18" bulbs, it has been working fine and running relatively cool (compared to the WH5 powering the two 36" bulbs over my planted tank).

10-06-2011, 01:30 AM
Making the acrylic box to house the screen was the second hardest part of the project (the hardest being cutting the slot in the PVC which I will describe shortly). The box is made from 1/8" clear acrylic and is just big enough to accomodate the screen and the PVC feed pipe. The width of the box was dictated by the width of the flange on the bulkhead.

I chose 1/8" because I thought I would be able to "score and snap" the plastic, not having a table saw with which to work. This method does not work very well. I ended up having to sand flat the scored edges because they would invariably snap on an angle. Sanding is hard work and doesn't even guarantee a flat edge. A router could have been used to square up the edges, but I don't have one of those either. If I were to redo this project I would use thicker plastic (probably 1/4") and borrow or buy the proper tools.


The feed pipe sits in slots cut out of the side pieces with a hole saw and a hacksaw.


This photo shows that it is possible to get by without expensive long clamps, so long as you have a good table, wood, a carpenter's square, and lots of small clamps.


The slot in the 3/4" PVC feed pipe was cut with a Dremel "cutting disk". It is supposed to be uniformly 3 mm wide and exactly as long as the screen. However it is hard to be that precise with a hand-held tool and I ended up having to redo my first attempt. I found that clamping the pipe to the table parallel to the table edge allowed me to slide the Dremel in a controlled fashion down the slot. By the way, this step will create a big mess with lots of fine white plastic dust, so don't do it in the living room like I did.


Also in the picture above is the screen, which is that plastic grid canvas/screen available at any craft store. The first three employees you talk to at the store won't understand what you're trying to describe, but trust me, it's there.

In the first picture in this post you can see that I elected to put the bulkhead in the middle of the bottom panel. I did this because my scrubber sits above, and drains directly into, my refugium; the bulkhead could just as well have gone through one of the side panels.

10-06-2011, 01:43 AM
The feed line is teed off of my main return. In the following picture (right to left) you can see the ball valve controlling the main line, the smaller ball valve controlling the refugium branch (partly closed), a short section of 3/4" vinyl tubing, a quick disconnect "cam and groove" connector (available usplastics.com), and an elbow feeding into the scrubber. The screen is attached to the feed tube with long plastic coated twist ties. Some people use zip ties, but the twist ties are reusable.


Please keep in mind that a vertical algae scrubber requires substantial water flow (e.g. an MJ-1200 would not be enough even for my modest scrubber). In action it looks something like this, though this picture does not have the T5-HO lights nor any algae growth.


Thanks for reading! Please reply with comments, questions, and suggestions.


10-06-2011, 04:06 PM
Nice write up! I considered making one when I was building my 180 setup but with how well my fuge is doing I didn't see a point.

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10-06-2011, 09:12 PM
Great write up on your scrubber. Keep up the good work.

10-07-2011, 01:10 PM
George, do you still have that LED over your fuge you won when Mark Vera came to talk?

Chilly, thanks for the encouragement!

My "refugium" wasn't really supposed to be a refugium but another display, so I don't have room for a giant ball of Chaetomorpha or anything like that. (Plus I've found that Cheato doesn't grow fast enough to put a real dent in dissolved nutrients.) I may have too many fish and/or feed them too much, which is why I still get Dictyota (a leafy brown macro algae) and Ventricaria (large solitary bubble algae) growing in my display.

10-07-2011, 09:58 PM
Yea still use ot on my fuge. My cheato grows at a pretty decent rate.

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11-29-2011, 12:19 PM
A seam split on the algae scrubber so I've taken it off of my tank. I guess this will allow me to do some scientific comparisons between algae growth in the display tank with and without the scrubber...


The main reason this happened is that the end cap on the PVC pipe was glued on ever so slightly too far, making the pipe assembly too short and fit too snugly. This caused the acrylic of the long sides to bow outwards in the heat of the lights, stressing the joint.

I'm not going to try to patch it or rebuild it at this time, but if I were going to rebuild it I would keep the following points in mind:

Use thicker acrylic, at least 1/4". It's easier to work with and forms a better joint.
Add "euro bracing" to the top edge of the box to reduce flexing and stress on the seam. This would also reduce possible splashing.
Put the bulkhead on one of the short sides rather than on the bottom. There is nothing wrong with it on the bottom, but putting it on the side allows for more flexible placement.