Ok, first I’ll order a GH/KH kit. Although my current test strips don’t show GH and KH there are other things like hardness and ph so I’ve took a photo that may help
with regards to food, (keeping in mind I have danios in the tank), I use bug bites, tetra crisps, flaked tetra goldfish food, sinking shrimp pellets, frozen bloodworm, snowflake and finally the food I’ve made. I have a feeding dish but I rarely see the shrimp in it. Maybe I need to drop the food near the back where the Java fern/bog wood is as they like to hide in and under that.
I use test strips weekly to measure nitrates/nitrites and they tend to be close to zero. I tend to do water change every 2 weeks but I agree that 10% doesn’t feel enough. Also worth noting that in the last water change I forgot to clean the sponge filter.
I’ve got a sponge filter, not big but apparently (according to Amazon it’s for 20 to 75 l) https://www.amazon.co.uk/gp/aw/d/B09Q2TZCS2?psc=1&ref=ppx_pop_mob_b_asin_title
I have been thinking of getting something so that I can run another sponge filter or sit stone from the same pump though