How to get rid of duckweed

Some people choose to keep duck weed in their aquarium but if not then you, like me, may find it to be a problem.

It starts as a few small bits floating on the top of the tank and then evolves into a plant that takes over the aquarium.

You thin it out with a new and two days later it has completely take over the tank again.

Fortunately it doesn’t block the light sop won’t effect your tank too much but it as a pain when it gets thick.

I’d seen on you tube the “overflow method” to get rid of it which in a really small tank would work, but mine was in my 190 litre corner tank –

Tipping it to overflow is not an option!

So i got thinking of another solution – Thinning with a net doesn’t work so here’s how I got rid of the problem completely.

cleaning duckweed on nano tanks

Removing duckweed from a tropical aquarium

This method will work on cold water aquariums too.

Step 1 – Bottle skimmer

This is a really easy thing to setup. Take a clean old plastic bottle (About 1 litre/ 2 litres) and cut the top off at it’s widest point.

This will be used to skim the duckweed off the top of the tank.

Then next to the tank setup a bucket with a fine mesh fishing net, just like what you’d usually use to scoop any fish out, and then balance it over the bucket (There’s a video coming further down to show this).

Step 2 – Skim and filter

Use the cut bottle in the tank and just push it a little under the surface so the duckweed and some water start to flow in.

Once the bottle is about 3/4 full take it out and check you’ve not caught any fish in it!

The poor the water into the bucket through the net. Keep repeating this until you’ve done a bucket of water.

At this point you can either change the water if needed of pour it straight back into the tank and keep going.

Once you’ve got the majority of it you can then just pour the water through the net over the tank to get rid of the last few bits.

Step 3 – Repeat daily

You’ll need to keep picking off other bits that appear.

They may have been stuck in your filter or in your plants but for 3-5 days other bits will keep appearing – do not just leave them or you’ll have wasted all your effort getting it clear as the spread will start coming back.

It should now be really easy to use the bottle scoop to get the odds bits out as it pulls the water into the bottle.

I’m sure if you are handier than I am you could build a filter into the bottle and just skim it that way and then tap the water out at the bottom – This would save lots of time if you had a really large tank to clear.

Have more issues or questions? Leave a comment below or Tweet me on @smalltanksuk

This is the only way I’ve found to get rid of the problem

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