How do I get rid of this slimy green algae?

[Yossu]

I have a freshwater tropical tank, 24"x12"x12", which houses an angel, six neon tetras and a small catfish (pleco I think). Substrate is gravel, filtration is via an Eheim canister in the corner. I have some Elodea planted around the tank.

My problem is that everything gets covered with a slimy green algae, which comes back as fast as I clear it. For example, here is a sprig of Elodea that I cleaned two days ago. As you can see, it's covered again...

I have an LED daylight light above the tank...

This is on for around eight hours a day. The tank doesn't get any direct sunlight, but does get some natural light from a skylight in the ceiling above.

Anyone any suggestions as to what I can do? Thanks

 

[GaryE]

First, that doesn't look to be algae. I see a bacteria, cyanobacter of some sort. and it is a major pain to eradicate. I get it in tanks that get natural window light.

I use a primitive attack. I cover the tank for a week, completely. A total blackout. It usually works, for a bit...

My tanks that don't get sun rarely show it. I stay with 25% water changes every week, keep the filters cycled but clean, and watch for overfeeding. But it is tough to beat. There are 'red algae destroyer' products, but they keep their ingredients secret, which I dislike, and they are pricey.

 

[gwand]

I controlled my algae problem by using artificial lighting only 4-6 hours a day, and reducing feeding to one time every other day. You can also use this safe product, Ultra Life blue green slime algae remove.

 

[Yossu]

Thanks to both of you for the quick replies.

I was wondering about a complete tear-down. I can move the fish to a temporary home, then clean out the tank, get new gravel and plants (I have plenty Elodea in another tank) and try again. If I'm careful, I should be able to cycle the tank without losing any of the fish.

Does that sound like a worthwhile plan, or am I likely to end up back where I started? I must confess that I'm not as good with water changes on this tank as with others, so that might contribute. If I were to tear the tank down, I'd make sure to do more regular changes,

Thanks again.

 

[gwand]

I would first make the changes Gary and I mentioned before trying a tear down.

 

[TwoTankAmin]

I have not had to go war with Blue Green Algae (aka cyanobacteria) for over 15 years. However, when I had it in a 20L it was ultimately WAR! I eradicated for good using the method below and then improving circulation and reducing lighting some.

1. Manually remove as much as possible via a small siphon.
2. Do a big water change.
3. Add only one dose of an antibiotic. I used Erythromycin (Fritz Maracyn). Follow the bottle directions for how much to add for your volume.
4. Blackout the tank so no light gets in for one 5 days.
5. Do not worry about the fish pr feeding, they will be OK.
6. Do another big water change and increase circulation some and lower light level- intensity and/or duration.

Note: I did the above only after other less stringent methods failed to work. Some folks do not using the antibiotic. I consider it very important in this late stage attack when all else has failed.

 

[Colin_T]

Blue green algae (Cyanobacteria). It wipes off in sheets or a film and smells musty. It comes in a range of colours including dark green, light green, blue, black, brown, red, pink and purple. It loves red light, nutrients, slow moving water and low oxygen levels.

Do a big (75%) water change and gravel clean the substrate every day for a week or two. Try to physically remove as much as possible each time you do the water change.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.

Remove ornaments and take them outside and hose them off.

Increase aeration and water movement around the bottom of the tank.

If you have an adjustable light above the tank, try to have it set on 6500K or use a cool white globe with a Kelvin rating (temperature) above 5000K.

Reduce the amount of dry food going into the tank.

If all else fails, find something like the Ultralife Blue Green Slime Stain Remover from Amazon and use that.

Server Busy

 

[Yossu]

Thanks to all of you for the replies. I'll have a go at it as you suggested, and see how I get on.

 

[MaloK]

What is exactly your led light specs ? How strong is the ambient light ? I think your led is too far from the top and it prevents it to have a good intensity in the tank.

How much water movement is there ? Cyano loves stagnant water.

How much water do you change per week ? Nutrients accumulation is a serious promoting factor.

 

[Yossu]

What is exactly your led light specs ? How strong is the ambient light ? I think your led is too far from the top and it prevents it to have a good intensity in the tank.

Not sure of the spec as I bought it years ago when I was growing carnivorous plants, and needed a strong daylight bulb. I remember that the colour temperature is around 6000K, but can't remember any more.

Ambient light is probably slightly higher than an average room, as there is a skylight not far from the tank. Doesn't get any direct sunlight due to the direction, but is quite light.

I used to have the light much lower down, but moved it up as I was getting overrun with algae (the real stuff, not this cyanobacteria). It's still pretty bright in the tank.

How much water movement is there ? Cyano loves stagnant water.

It's not like a raging river, as my understanding is that angels and neons don't like too much water movement. Having said that, the filter output points away from the corner into the middle of the tank, and there isn't much in the way of obstruction, so there should be a reasonable amount of movement. I know when I dump some duckweed in there, it sails around the surface!

How much water do you change per week ? Nutrients accumulation is a serious promoting factor.

Ahem, looks embarrassed. When I'm being good, I do about 30% once a week, but I must confess that I've been very poor at this recently. When I've had a go at it, and hopefully got it under control, my aim is to be a good boy and go back to more regular changes.

Thanks for the reply. Any further comments would be welcome.

 

[Colin_T]

A light with a 6000K globe is fine. The most common cause of blue green algae is excessive nutrients and uneaten dry food is the biggest cause in aquariums.

 

[Yossu]

A light with a 6000K globe is fine. The most common cause of blue green algae is excessive nutrients and uneaten dry food is the biggest cause in aquariums.

So more regular water changes and cutting down on the food should help?

Thanks again.

 

[MaloK]

More regular and bigger than 50%

 

[Colin_T]

So more regular water changes and cutting down on the food should help?

Thanks again.

Yes, less dry food and more frozen or live foods. And more water changes and gravel clean the substrate every time you do a water change.

 

[Yossu]

Thanks to both of you for the replies.

@MaloK - I'm surprised at such big water changes. I thought these were bad for the fish, as the sudden change of temperature and chemistry would shock them. I've always gone for 30% max.