@Odai: we have plans to offer an alternative firmware for the aquaero LT so it can be used as a slave device. It would integrate like 4 new fan channels and additional sensors too. But this will not be available from the beginning so expect it later. Due to the internal management of the channels this will work with only one aquaero LT and you will also lose the option to add 6 poweradjust since 4 channels will be taken by the aquaero LT in this case, so you have only two left for poweradjusts.

The powerbooster is an upgrade option which is only compatible with the aquaero 4. The aquaero 5 does not need this kind of upgrade.