How many water changes will it take to beat algae?


A reader asks what water changes are advised to keep algae away from their tank as much as possible?

Q) I’ve just set up my first ever aquascape. It’s a 25 l tank with Tropica substrate topped with gravel, and Dragon stones. What water changes over next few weeks would you advise to keep algae away as much as possible? I’m using Easy Life Profito and dosing liquid carbon daily.


A) JORDAN SAYS: I would recommend following a water change schedule such as the one outlined by Aqua Design Amano (ADA). They advise to perform a one third water change every day in the first week, every second day in the second week, every third day in the third week and then continue to change one third of the water weekly in the long term. You may want to consider doing a larger water change than this if any algae issues occur.

Be aware that Easy Life Profito contains no nitrates or phosphates, which is something you might want to consider using after two months or based on your plant health. There are many all-in-one fertilisers on the market that contain nitrates and phosphates.

Liquid carbon products have many names, but the main chemical is usually glutaraldehyde, or similar, which is a biocide. When spot-dosed directly onto algae it can be an effective tool to control it, but it is not an effective carbon source. There is no measurable amount of CO2 generated by using these products when tested using store-bought test kits. Rather than dosing this daily,

I’d instead only spot-dose algae as and when needed. Nevertheless, chemicals are not the best way to resolve algae issues and fixing the route cause should be the priority.