yellow/green ...
i would guess greenwater/phytoplankton
most people consider this an eye-sore and want it cleared up
as for clearing it up, ... hmmm, ...
i've heard just let it go, it will gradually darken, your water will get greener and greener, then suddenly one day it will all be gone
actually i had that experience in my tank to support it.
but with a bucket of greenwater i collected from a local stream i'm trying to recreate that so i can test "what is going on" (because i can't get any greenwater going in the tank again no matter how much new greenwater i add, it all dies, ... and this is many months later)
once your greenwater dies, your tank is pretty much completely immune to the stuff forever afterwards
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if it is greenwater, ... you won't ever get rid of it with water changes, those are a waste of your effort in doing anything about it, it's always going to come back
you could try blackout, ... wrap your tank in a heavy blanket for 3 or 4 days, ...
this is hard on your plants, and harder on the greenwater i hear - it is expected to kill the greenwater and solve the issue
-having any source of light will feed the phytoplankton and undo what you wanted (to kill it off)
-make sure your fish are well fed before you start.
i'm not a particular fan of this.
but i'm a little strange
if you have a slight greenwater issue like you do, ... you could invest in a freshwater clam which will eat the phytoplankton, ... most people who try clams fail because it starves (no food), you've got food (phytoplankton)
could go for more exotic and hunt down freshwater sponges (i have no idea if other fish will eat these - i assume so, but almost no one has freshwater sponges in their aquarium - you could be one of the first)
-but i'm hypothesizing on freshwater sponges, ... you thought clams in aquariums was hard to find information on, ... try sponges
...
so it's up to you
most "cures" are usually successful (regardless what you pick), but like anything nothing is a guarantee (although water changes will never work for greenwater issues)
you do have options (if you want) on trying some more exotic things in your tank others simply can't (clams and/or sponges)
or you could try daphnia - not quite so successful i hear as they're large enough your fish will eat them all long before they could do anything to keep your greenwater issue manageable, ... then once these zooplankton are gone your back to square one - a greenwater issue
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i don't have answers on what to do as it's up to you
i have ideas that say you've got lots of options and it's up to you how you wish to proceed.