Black Algae Problem

[Funktion]

Hi,

I am currently on my second Juwel tank. The first was a Rekord 60, and I now have a Rekord 120. Both of these tanks have had the standard Juwel 'box' filter installed, and my other tanks use Fluval internal filters. I think the Juwel filters are an excellent idea - I especially like the integration of the heater - but in both tanks I have found that I get a gradual buildup of fluffy black algae. This attaches itself to virtually everything in the tank - the glass, the outlet of the filter, slate, leaves - everything! I have never had a problem with this type of algae in my Fluval filtered tanks, so I was thinking maybe the venturi system and increased flow of the Fluvals kept the water more agitated throughout the tank than the Juwel filter does and prevents this algae from attaching.

My tanks are always well lit but also well planted, and I have never had any real problems with algae other than in these two tanks. The occasional brown film or green spots on the glass, but these are easily scraped off whereas the black algae cannot be destroyed! I can scrape it away and gather it all up to dispose of, but the 'roots' grow back pretty damn quickly. The only way I have managed to remove it from the slate (and beautiful slate it is as well - well worth salvaging) is to move the stone to a coldwater tank - the algae hasn't made a return in there.

I was wondering if anybody else had had a similar experience? Could it be the Juwel filters or is it just a strange coincidence that both the tanks with which I have experienced this type of algae have had the same filtration?

 

[JamesC]

It is called Black Brush Algae (BBA) and it's appearance is usually CO2 related. Take a look at http/www.theplantedtank.co.uk/algae.htm for identification and also for remedies. How much light do you have in your affected tanks and also do you add CO2 to them?

James

 

[Funktion]

Cheers for the algal ID James.

The 120 litre tank is currently lit by a 30W 36" Sun-Glo strip, and I haven't yet branched out into the world of CO2 systems as my plants seem perfectly happy without. However, as your website suggests, additional CO2 could be a good preventative measure for algae.

I was under the impression that in a reasonably-heavily planted tank the plants themselves would out-compete algae for nutrients. Is this not the case, or is it merely an over-simplification? Go into as much depth as you want, as you seem to know your stuff and I'm a qualified microbiologist (now watch as I come back with some more stupid questions!)

 

[JamesC]

As your tank is a low light tank you don't need to add CO2 but you do need to try and keep what you do have stable. When doing water changes let the water stand for a day before adding it as this will dissipate any CO2 that is in the water. Often tap water is loaded with CO2. Plants like stability best of all so this is what you need to try and maintain. You could always add an alternative carbon supplement called Seachem Flourish Excel. This has the benefit of not only adding carbon to the water but also it will kill off you black brush algae. There are a few plants that are affected by this stuff - I've got a list on my website somewhere.

Not 100% sure what keeps algae from growing but lots of happy plants and good water seems to do the trick. Struggling plants or poor water lets the algae in. I think the old idea of plants out competing algae is flawed because like myself a lot of people keep the water column constantly supplied with nutrients. Some people still do think that you have to try and strip the water column of NO3 and PO4 in order to keep algae from growing, but they seem to go to a lot of trouble and end up with more algae than people having nutrient rich water columns.

James