BROWN ALGAE ISSUE

[Delboy50]

TANK 48L 15W 18H

Hi,

My tank is 2 months old now. I have 8 decent sized plants that are growing well.

I have noticed that brown algae is growing on top of some of plants nearest the lights.
Also it is growing on the drift wood again that is nearest the lights.

I have had both the LED lights on & they total 50 watts and the tank is bright when they are on.

I have now reduced it to 1 light for 10 hours a day.

What has surprised me as my nitrates are low i though the plants would out complete the algae.

Any thoughts would be appreciated.

Thanks,

Derek

 

[Essjay]

10 hours is a long time unless you have plants which need a lot of light. I have low light plants and mine are on for 6 hours a day.

Do the lights give the K rating? Some lights have a K rating over 7000; there is more blue the higher the K rating and this encourages algae to grow. Ideally the lights should be around 6500K.

However, the tank is just 2 months old and diatoms are common in new tanks. Does the brown algae wipe off easily? If it does, that's diatoms. It should lessen as the tank matures. But also look at the rating of the light and think about reducing the 'on' duration.



Nitrates are often low in planted tanks. You don't mention having fish, but plants use ammonia faster than filter bacteria and they don't turn it into nitrite and on to nitrate. If tap water nitrate is low, tank nitrate is often low in a planted tank.

 

[Colin_T]

Picture of the algae so we can ID it?

 

[Delboy50]

Hi,

Thanks for the responses.

The plants are Elodea Densa & i will ask at the fish centre what the other 2 plants are (same type).

I do not know the K rating of the light units. I did check back on my amazon order but no details are provided.

I do know there are 25 watts each and were sold as full spectrum lighting. Each unit has 11 blue/green/red lights and 33 white.

I put the moonlight setting on for 90 mins at night. The fish seem to like it and they slow down and move very low in the tank.

Yes the algae is very soft and wiped of easily the last time i did it.

I am doing a water change tomorrow so will clean it off then.

The plants I can't remember the name off about a week ago started turning the leaves upward. When i bought them they were flat and out stretched.
I am wondering is that because they are getting too little or too much light.

Thanks

 

[Delboy50]

By the way i am not good with the IT side of things i transferred some older photos to my PC. I was going to post a few pictures of the tank.

Apparently they are in the apple I cloud. So i will need to ask how I find them

 

[Essjay]

Does the light have a brand and model number - that should be on the Amazon listing.

10 hours is still a long time; you'd know if you have plants which need a lot of light as those also need added CO2 and lots of fertiliser. Elodea is a low light plant; if you could find out what the others are, that would help.

I would reduce the duration by one hour a week down to 7 hours. And reduce the moonlight time as well as algae can use blue light while 'proper' plants don't.


The brown algae does sound like diatoms, which as I mentioned earlier are common in new tanks. They usually disappear as a tank mature, which is usually quoted as being mature 6 months after cycling has finished..

 

[Delboy50]

Hi,

I reduced the light on period to 7 hrs. Within a few days the brown algae has started to die back. When I checked tonight it has almost disappeared.

The plants are doing well so as was suggested it was simply too much light.

Thank you