Tested my water all good tank has now cycled.
Yes it is the one from improved living. I use the first for filter media second my cheato refergium and the Tunze 9004 only fitted in the third chamber with very little modification
no Po4 rise as I clean the top filter wool every other day and the rest once a month. (weekly 10 l water change)so your first chamber has your actual media in ? dont you think that it will get dirty and cause a PO4 rise ?
do you have a light on your chaeto ?
my chamber from 1.heater and Filter sponge i clean once a week when i do a water change , 2nd skimmer , 3rd has my bio filter media , 3rd return pump.
your tank looks smart i would lose the chaeto but dont think it will have much effect in our tanks