Streetwise

Here is a very informative Aquarium Co-Op article on Cyanobacteria, including treatment: https://www.aquariumcoop.com/blogs/aquarium/blue-green-algae I'll put out the bat signal for @Daniel, @Hobbit, and others for some science guidance.

When I was keeping marine aquariums, I got it a few times, and I would remove what I could, and then stir the sand to bury the rest. I don't know if what I did with the sand was recommended or not, as my only source of information was my local fish store. If it is just on that decoration, you could simply remove it, and scrub it. We have to deal with outbreaks on on Lake Champlain. According to the Vermont Cyanobacteria Tracker: "Cyanobacteria grow well in water that has high amounts of nutrients like phosphorous and nitrogen. Cyanobacteria can multiply quickly to form surface scums and dense populations known as blooms, especially during the warm days of late summer and early fall." This makes me think that you might have excess nutrients, and that heat may play a part. I'm sure that there are other forum members with more knowledge on this topic and they should be able to add more about treatment and biochemistry.

With that color, it looks like cyanobacteria. Here are the threads tagged with that: https://forum.aquariumcoop.com/tags/cyanobacteria/

Great start! I can't wait to see how it develops. Those filters are nice and stealthy behind your wood and rocks.

Don't read your Co-Op emails! Save the surprise for an unboxing.

I have bought a few different video cameras, but I keep pulling out my iPhone for all my impromptu photos and videos. A good phone camera is always nice to have because it is always with you. I’m tempted by the new iPhones with magnetic lens mounts. For a quality webcam, I love the Logitech Brio 4K. Other folks will have more suggestions for dedicated cameras.

I got an inline Tetra kit, which would fit standard-size Python-type tubing. I got it to kitbash into a filter, but I might test it with the turtle tank that I take care of. I’ll report back. It has an inline power switch, which is nice.

As a certified tannin sommelier, I approve!

I support a woman’s right to proper pockets!

You can also find Water Lettuce at a garden center, which is where I got mine. It is larger than Duckweed but easier to manage.

@FlyingFishKeeper, please let us know when the shrimp arrive on that piece of wood.

@Garren B, I believe it is Peperomia Obtusifolia, or Baby Rubber Plant, or some close relative. I have found that I can grow out waxy-leaf houseplant cuttings in my water, if I keep the the bulk of any leaf out-of-the-water. The plants in the photo are wedged into wood, and have sprouted roots.

I rearranged my room, and put a light on the leaf bucket. I need another 5 gallon bucket for the extra light I have now.

As Daniel alludes, with enough plants, your inhabitants will be fine. I could keep all of my Nano fish, and Neo Shrimp tanks without filters. I like sponge filters for moving water, and collecting things in foam, including beneficial bacteria. I mostly top-off, and rarely change water. I don't plan on cleaning my sponge filters. They are part of the scavenger buffet.

Excellent!