I have 6105s x2 for 11 yrs that have been so awesome and still work great. They are older (pre 2015?) versions that came without controller. I had them going back in the day with my apex but the control cable always fell out and became a pain so I sort of stopped controlling and just used them at 100% flow all the time for fish only/ softies set up. Now I am suffering from coral fever again and want to set up waves / control speed. Trouble is I can’t get them to have variable flow. The apex will turn them off and on but won’t change speeds. Not sure how to trouble shoot this. Is it my cable? Is it the programming? Is it the pump? Any ideas. Thx