2 cubes sounds like alot to feed. It would help if you gave us a list of how many fishes you keep and your total tank volume.
Most of us are not using that brand of phosphate absorber so i cannot comment on how good it is. Do you see a drop in phosphate readings after you change out the absorber?
letting the water age will not remove phosphate, it will not even remove chloramine.
Green colour mud is not enough. You should consider changing to a better skimmer.
Also, most hobbist testkit can only detect orthophosphate. So your actual phosphate readings is much much higher.Anything above 0.3 will seriously inhibit calcification.