You say you change the filter after a water change?
I'm thinking you mean clean it out?
If this is true, then this is your problem.
By wiping out a lot of the bacteria, along with the overcleaning in the tank, there isn't enough bacteria to support your bio-load, so basically every time you clean anything, your tank enters either a mini-cycle, or purhaps if you do it even more often than i suspect, then it isn't even cycled at all your tank.
My canister only ever gets cleaned when the flow gets diminished too greatly. Canisters are really nothing but a safeheaven for bacteria, and thats what i think they are best used for.
Don't clean your canister filter.. No need to even open it
Use a powerhead if you feel your gonna lack flow when the canisters flow gets diminished by not being cleaned.
Trust me it is still every bit as effective, even though the flow is diminished.
Stable balance, and slow and steady is always better than fiddling.
Right now you can go ahead and grab a bottle of chemicals to remove the cloudyness.
after adding it, just leave the tank alone, without any cleanings or water changes untill the cloudyness dissapears, then do a 25% water change and then 2 days later do another 25%.
From now on you should be doing 20-30% water change once a week, without cleaning the filtration system.
Ps. your water is off the charts high because there isn't enough bacteria to feed on the wastes.