Hi guys! About half a year ago I shared with you my concern about super weird bubbles and huge algae growth in the aquarium. As a perfectionist whenever I would look at the tank my eyes bled – it looked so dirty as if it’s a swamp but the idea that my shrimps were happy made me feel happy too so I got used to the look of their filthy abode and was waiting for them to start multiplying. Even though the contrary has occurred… Instead of a berried shrimp I found a dead one The rest of the shrimps seem to be pretty normal. Am I doing something wrong? There is still an excessive amount of organics, even more than before. Bubbles disappeared but the tank looks like it was completely captured by algae.
That is a lot of bio film / algae. If it is not getting removed by the shrimp and snails (i.e. is getting thicker) - I would manually remove as much as possible and do a water test. If any water parameters are off do a partial water change too.
Thanks for your advice guys! I should indeed get some snails, how many do you think I need for a 20 liter tank with 8 shrimps? All the parameters are fine, haven't fed the shrimps for more than 8 months now (when we came to the conclusion that they have food for years ahead ). Also will you recommend to get rid of moss balls in my case? Do they act as an extra source of organics?
I'd throw in 20-30 snails and remove the moss balls if you didn't buy them from Mustafa on this site. Slowly decomposing marimo will add a lot of extra stuff, yes.
That's not "normal" biofilm. It seems like you have mostly cyanobacterial growth there. Yes, the "brackish water snails" will definitely take care of that over time. But they need to multiply first. Also take out the marimo balls. You must have had LOTS of nutrients in your substrate when you started the tank. Rinsing the substrate thoroughly is usually a good idea. As was suggested, I'd try to remove sheets of the cyanobacteria manually if you can to help out the snails with their job in the future. That will accelerate things.
– it looked so dirty as if it’s a swamp but the idea that my shrimps were happy made me feel happy too so I got used to the look of their filthy abode and was waiting for them to start multiplying. Even though the contrary has occurred… Instead of a berried shrimp I found a dead one 
The rest of the shrimps seem to be pretty normal. Am I doing something wrong? There is still an excessive amount of organics, even more than before. Bubbles disappeared but the tank looks like it was completely captured by algae.
