The water does not contain much of the bacteria needed for cycling. The bacteria live on all the surfaces including gravel, plants, filter media, etc.

Doing those water changes will reduce nitrates (or ammonia, and nitrite), so this is the most important thing. Cyano-bacteria stinks like rotten seaweed. Also keep food restricted.

Good luck. It'll work out with time as I think you have a handle on this.

keep us posted.

Sponge filters come in all sizes and shapes and many are designed to slip over a filter intake, and they're cheap.

This not only improves biological filtration, but keeps small fish and 'shrimp' from getting caught or sucked up.

And yes, it's happened to me when filter intake fell off for a period a couple times. Poor otto. Poor ghost shrimp. Poor coolie loach. RIP!

So, I may not have the issue under control. I think it might be cyano bacteria. It is showing up everywhere now. It is primarily on my java ferns but I find it on the sand and decor. It is fibrous, slimy, and looks like frayed green thread. It is a royal pain in the butt!