You may want to increase your water changes to 20% per week and 40% once a month (or even more). All signs point to too many nutrients in the water causing an increase in algae and worms. Make sure to include vacuuming the gravel in the water changes.
Treating the water with any anti-algae stuff will not get rid of those nutrients. In fact, since the algae are using them up, it'd likely create a more unhealthy environment for the fish.
Last edited by Imp; 11-29-2019 at 03:23 AM.