is this brown algae and some kind of mould?

[zebby82]

hey folks! i'm new to the aquarium world and so far it is super fun. love my fish, shrimp, and esp. the plants.



my 75L tank is about 3 months along. everything has been healthy, i test/chg water weekly. all my parameters are in the recommended range for my fish and i have a full-spectrum led light. let me know if you need more info about my tank.


i have this brown colouring happening all over my plants. i recently just bought a tank from a reputable aquarium store in town. every since i planted it a few weeks ago, i am seeing this brown stuff all over the grassy plants that have been in there since the beginning. my mosses look fine. i also noticed on my lucky bamboo there is something that looks more like mould growing on the stalks.



i weekly add half the recommended amount of API leaf zone, and i add 1ml of Seachem flourish excel carbon every 2-3 days to just lightly fertilize the tank (i didn't want to overdo anything since i'm new).


i'm hoping someone can tell me how to get rid of whatever this stuff is - i don't mind the green algae growing on the rocks and plants - my shrimp love nibbling on it. but this brown stuff is not attractive...



thanks a lot for any advice you can share! pics are attached!

[Colin_T]

Hi and welcome to the forum

The short green fuzzy stuff on the stem of the lucky bamboo is just green algae. Lucky bamboo is a terrestrial plant and its leaves need to be out of water. The stems will naturally develop algae on them when kept in aquariums.

The brown stuff is either diatoms or blue green algae (Cyanobacter bacteria).

All algae grow from excess light, or excess nutrients, or not enough live plants to use the light and nutrients. If you don't have many live true aquatic plants in the tank, you might have too much light or nutrients in the water for the plants you have.

You don't need to add carbon to aquariums with plants unless you are trying to grow terrestrial plants underwater. Then you need to have lots of light, lots of nutrients and carbon dioxide (CO2). In an average aquarium, there is plenty of CO2 produced all the time by the fish and bacteria in the aquarium. It's continually being produced all day every day, and normally provides plants with all the CO2 (carbon) they need. There is also CO2 getting into the aquarium water from the atmosphere.

Maybe post a picture of the entire tank and we can see how heavily planted it is.

In the mean time, reduce the carbon and other fertiliser, reduce the amount of food going into the tank (especially dry food), and maybe do a water change.

Regarding water changes, you should do a huge (75-80%) water change before adding more fertiliser. If the plants don't use all the fertiliser and you just add more each week, it can slowly build up over time and then suddenly poison everything in the tank. Doing a huge water change before adding more fertiliser will dilute any leftover fertiliser, and reduce the chance of overdosing.