Setting Up An Algae Scrubber

In my PRL and PFR tank, I've having issues keeping nitrate level low (it is around 40 ppm). One way is to keep doing water change but it's too much a hassle and not conductive to keeping shrimps to have water parameters constantly changing. So I've decided to set up an algae scrubber and show you how I did it.

What you need:

1. External breeder box (I got the largest Satellite one with a length of 30cm)
2. Air pump
3. Light (Doesn't matter which kind but the stronger the better)
4. Screens with Algae
5. Aluminium foil

The external breeder box will be used to house your algae and you can't use an internal one as you want to encourage algae growth IN the breeder box, not in your tank (well if you love algae in your tank, then you won't need an algae scrubber....).

You'll need an air pump to drive air into your breeder box.

For light, a powerful halogen lamp is the best but it consumes a lot of electricity and it emits a lot of heat too. Another good choice is a fluorescent lamp but I chose to go with a LED lamp for power saving reasons. Don't worry too much about the wavelength of the light emitted, just go for the one which gives you the most wattage. I chose the 26cm Aquasonic LED lamp as the length is just nice for the breeder box, it can be attached to the box easily, and it's one of the cheapest LED lamp available.

So this is how it will look like at this stage:

Ideally, the lamp should be as close to the water surface as possible but this is the best I can do.

For screens, you can get plastic mesh screens like these:

I had these lying around but I initially got them from Daiso for $2 each. Before using them, make sure to scratch up the surface of the mesh. The algae will be able to take root better on the uneven surface.

To get algae to grow on them, pour some tank water into a container with the screens. Just place them in the sun for a week. It helps if you add fish or shrimp food as the additional ammonia and nitrate will help to encourage algae growth.

My screens don't have algae on them yet

The last thing to do will be to wrap the container in aluminium foil. The foil will serve to reflect light within the container so that every part of the box will be lighted. You can even wrap the entire box AND the lamp so that there is no light leakage but I didn't go that far.

The final product will look like this:

I typically switch on the lamp at 7am in the morning when I leave for work and switch it off at around midnight when I go to bed. Plants can only photosynthesise for 18 hrs a day so it's pointless to leave your lamp on 24/7. I can't comment on the effectiveness of this setup yet as my screens aren't filled with algae but I'll give an update in a few months' time. Hopefully, it'll be able to reduce my nitrate level to zero and keep it that way.