Too much algae ruins the tropical fish tank hobby for many people. The green slime coats the glass, plants, and gravel, and a beautiful fish tank is turned into an ugly embarrassment.
Don't give up! Here's a five-point plan for dealing with too much algae in your tropical fish tank.
1. Remove as much algae as you can
You know when you can hardly see your tropical fish, too much algae is making your fish tank a misery. The first thing to do is to remove as much algae as you can. This is the start of the fight back, and a cleaner tank will inspire you to prevent algae permanently. Collect and remove green algae by twirling a cocktail stick through it. Algae magnets will clean the glass of most algae - for stubborn spots use a toothbrush or an old credit card. Discard any plants covered in algae, and remove decorations and wash the green slime off.
2. Reduce the nutrients (short-term fix)
Your tropical fish tank already looks better, but the algae will return double quick if you don't take the next step. Perform a partial water change and remove up to 40% of the water from the aquarium. Get rid of the detritus and algae you scraped off in step one. Replace with clean water - add an aquarium dechlorinator to your tap water first, or better yet age the water for 48 hours in an old tank or safe bucket. If your tap water has a lot of nutrients in it, you will need to consider using a resin or a reverse-osmosis unit to clean it up first, otherwise you're just adding too much algae food back into the tank.
3. Reduce the nutrients (permanently)
To keep the nutrient level down - and so starve algae of the phosphates and nitrates they need - you need to look at three factors. Firstly, make sure your tank is not over-stocked with fish. Secondly, ensure you're not over-feeding them. All food added should be consumed completely within five minutes, and there should be none visible on the floor of the tank. Thirdly, start a regular water change regime to keep refreshing the old dirty water with clean water.
4. Increase the planting
Algae will smother plants in a badly maintained fish tank, so the first three steps are vital to get it under control. Adding plants to a tank where the algae is in retreat will finish the job, though. Cheap stem plants grow quickly and absorb a lot of waste, reducing the food for algae. Floating plants can spread very rapidly to block out the light, further suppressing the algae. Floating plants will also absorb a lot of nitrate and phosphate.
5. Consider adding CO2 fertilisation and better lighting
If plants don't grow well in your aquarium, you may need to consider upgrading your lighting and adding CO2 to the water. It may seem odd to add more light, but plants in a well-kept tank will stop too much algae growing, so it makes sense to get them established. CO2 is much more important to plants than algae, so again by feeding the tank with CO2 can encourage plant growth rather than too much algae. CO2 can be cheaply added via a DIY kit, so it needn't cost too much.