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New tank - long grey / light brown algae strings

Chris 2020

New Member
23 Mar 2018
Hi all,

I have a newly setup 75L heavily planted tank, that I’ve been cycling for about 5 weeks. It got hit with long greyish, light brown algae strings mainly on the the moss around week 3.

Mostly all plants were grown from culture pots and have grown like a rocket in Tropica soil, with medium co2 running one bubble every two seconds & 16W of LED. Most of the plants are easy & medium category.

The algae is very easily removed by combing with a toothbrush, and once out of the water looks much more brownish.
Once removed it strangely reappears again by the next day, just as bad, but never on the glass or hardscape.

I Initially started the cycling off with seachem stability & am still dosing prime every couple of days, owing to 1ppm nitrite. Nitrates aren’t too bad at 25ppm & I’ve been doing 50% water changes twice weekly after clearing the algae.

Please see the attached picture, where you’ll also notice it strangely looks like cobwebs!

I found another picture of something looking the same on a new tank, mentioning it may be filamentous diatoms?



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