# How to get rid of brown/red algae on glass?



## bugman2494 (Sep 23, 2008)

Hi all,

I have recently started dosing PMDD in the 220 litre tank in order to get red growth in the rotala colorato, hygrophila 'sunset' and rotala macrandra. This has worked perfectly with the stems becoming blood red/bright pink however it has also set off some brown/red algae that grow on the glass. This algae is similar to the green dust algae however it is not soft like GDA, instead it is extremely hard to get off the glass. I have tried using the magnetic algae and the toothbrush without success. I have tried using my nails (which is bad on the glass) but even with my nail scraping against the glass, little algae comes off the glass. 

I dose 6mL daily with weekly water changes of 20%. Lighting is 2x54W T5HO.
The PMDD method:
http://www.aquariumlife.com.au/showthread.php/2734-Dry-Fertilisers-Source-and-Recipe

Picture of the algae








You can see some green dust algae in this picture but its the hard red/brown algae that is the problem


















Thanks,
John


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## jedimasterben (Aug 21, 2011)

I bought a common pleco when my 55gal had brown algae, he sucked it dry (well, in the way that an aquarium full of water can be sucked dry :icon_mrgr) in about two hours. Promptly moved him to a different tank as to not ruin any plants and things and there he waits until I need him again. This may not be the best course of action for everyone, but it cost me $3.


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## londonloco (Aug 25, 2005)

I have green spot algae crop up on some of my larger tanks. It is also harder to get off. I use a 3$ scraper that you can buy $2 (for 4 blades) blade replacements from Ace Hardware. I've never scratched a tank using this blade. I looked on the Ace website but it's not there to show you....


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## DarkCobra (Jun 22, 2004)

That is Green Spot Algae (GSA). You can see the green color on the larger spots, even though some of it looks brown.

If this is a glass aquarium, a credit card or a razor scraper remove it fairly well. If acrylic, the Original (not any other) variety of Mr. Clean Magic Eraser works best. I have no idea if they sell that down under.

GSA appears when phosphate is limited. PMDD has no phosphate. It's a old fertilizing system, and it's been years since I've seen anyone using it. These days, reds are usually improved by limiting nitrate rather than phosphate, just enough to get the desired effect.


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