Hi Everyone, we have a 4ft tropical fish tank and have a serious blanket weed problem! We don't keep the tank in direct sunlight and the light is on from about 12 noon until 9pm. Bulbs are correct for the tank but can't seem to get rid of this problem! We keep taking it out only for it to regrow again?

Anyone any experience of this and can help in trying to get rid of it?

Can't get real plants to live it either! We have checked the Nitrite/Nitrate and all good - any suggestions?

Whoops, posted in wrong bit - can you move to 'general' fish chat please MOD's?

This 'Blanket Weed' (actually algae; and most likely Hair algae) won't go anywhere until you've sorted out the real problem that's causing it to grow. Excess nutrients, swinging CO2 levels and a lack of live plants (assuming you don't have fish that won't eat or physically demolish plants) will all contribute to an algae problem.

You don't specify the actual nitrate level, or the phosphate level. Both are the main driving nutrients behind algae problems, however they aren't usually a problem in well-planted aquariums with fast-growing stem species since the plants naturally out-compete any pest algae for the food. Are you using a liquid or strip/tablet test kit and how old is the nitrate test kit? I ask this because test kits vary in reliability and the reagent chemicals in nitrate test kits have very short shelf lives.

I'd advise testing again for nitrate and phosphate; and cut down the photoperiod to no longer than six hours. How many fish are in the aquarium? Does the tank have a filter and if so was it cycled?