Ahhh, sorry! I had the aquaero 5 in mind since almost all questions of the last days were about the new one
Of course you can still use them with the old aquaero. They will be regulated through the voltage in this case. Keep in mind that the maximum allowed load of each channel is 10W (15W with powerbooster) and the overall load of all channels combined should not exceed 30W (45W with powerbooster).