Now let’s answer the first question most aquarium folks have about algae scrubbers: Should you buy or build?
Before the year 2010, there were not really any commercially available algae scrubbers available for purchase.
Fast-forward to today: Now you can buy tiny-to-medium size algae scrubbers in the upflow style as well as medium-to-large sizes in the waterfall styles.
In terms of doing it yourself (DIY), there are discussions on aquarium message boards that detail just about every algae scrubber that anyone’s even attempted to build—complete with growth examples and nutrients measurements completed over time. There are some truly amazing DIY scrubber builds out there.
We won’t go too deep into specific DIY plans in this article, but there are many available online. You may even find some on this very forum! If you’re super curious, you can check out builds going back 20 years on AlgaeScrubber.net.
A DIY algae scrubber can be made fairly easy if you are skilled in building stuff. The typical materials of PVC pipe, acrylic sheet, glue, airline tubing, etc. are needed, just as if you are building a DIY reactor, overflow, or sump.
One difference with algae scrubbers, however, which makes them a bit more difficult, is the lighting that’s needed for the growth. Not only are you now dealing with electricity, but unlike DIY display lights which are above the tank in a dry air environment that you rarely touch, the lighting for an algae scrubber is in a humid or wet environment (or even underwater) that you touch daily—with wet algae dropping on top of it—all while possibly standing on a wet floor (maybe even with bare feet).
Long story short, you probably won’t want to make a complex algae scrubber your first-ever DIY project!
Some advantages of buying a scrubber are that you obviously don’t need the time or space to build one. But other reasons are that it’s hard to DIY some types of scrubber designs, even if you are good with DIY. Things like underwater lights for upflow scrubbers, or gravel-epoxy surfaces for algal attachment, or the long slot in a waterfall pipe, takes a few tries to get it right (meaning your first try will probably not work).
Buying a pre-built unit, however, is limited to what is for sale. Currently the only models available are waterfalls (which Santa Monica Filtration invented in 2008 and are now made by SMF and others) and upflows (only made by Santa Monica Filtration), and these are in certain sizes only.
There are a very few number of horizontal river models. However, these come from China and are tiny without any lights. And there are no dumping bucket designs available at all, probably because of their complexity.
The biggest advantage of DIY is, of course, saving money.
Most $300 commercial models can be DIY’d in a week for $60 in parts, and most of the costs is in the lighting. But DIY also lets you choose the exact style, size, and layout you want to fit into your exact space. If you need a very large model, such as for small exhibits at public aquariums, you will have to DIY.
DIY waterfall styles are generally going to need some acrylic or plastic gluing, unless you can find the proper size plastic box to start with. Cutting the slot in the waterfall pipe is the hardest part, and although it can be done with a Dremel moto-tool cutoff wheel, most people end up doing it over again with a table saw, router, or other shop equipment.
The lights are easy. Usually low cost Chinese plant-grow lights can be used from eBay, as long as you follow safety steps properly. Most DIY folks can do the PVC pipes, so that’s not a problem. Waterfalls are not really suitable for freshwater because the growth gets long and clogs drains and pumps. Also, waterfalls work best when placed over a sump — not externally on their own — because they can overflow, leak, and also drip from the waterfall pipe.
DIY bubbling upflow styles can be the easiest if they are similar to the Hang-On-Glass styles that Santa Monica Filtration makes.
These styles need no acrylic gluing or PVC pipe. The LED lights just stick to a plastic cover on the outside of the sump or tank wall using magnets or suction cups. The airline tubing for the bubbles is as easy as a goldfish tank. Cheap LED lights and a power supply from Ebay will do because they stay dry and are low voltage (no 240/120 volts at the light).
These designs might be suitable for first-time DIY projects if you can get help with the lights and are great for freshwater too because the long growth is kept mostly inside the growth compartment. Lastly, they can’t overflow, leak, or drip because they are already underwater.
DIY horizontal rivers are relatively easy to build — at least the river water part is. But again, the lighting can be a challenge over the long narrow pathway. One workaround for this is to put it under your display lights, but that’s too cumbersome and unsightly for most people. And if you put it over a sump, these designs tend to cover the top of the sump like a lid, so you can’t get access to anything.
If you have multiple tanks, a good piece of advice is to first try a scrubber on the smallest aquarium. Especially if it is freshwater, because that way you can get a feel for placement, lighting, cleaning, noise, etc. before working up to a bigger one.
Meanwhile if you want to take a look at modern algae scrubbers, here is a Santa Monica SURF2 floating model — shown below floating in a saltwater reef pond.
If you missed the first entry in this series, read The Complete Guide to Algae Turf Scrubbers: Part 1 to learn more about the history of algae scrubbers.