Do you do a half cube total for the two tanks or just half a cube between the two tanks?
I have changed up my feedings a lot between my tanks. I really struggle to cut the cubes so I usually melt them & try and use them in a day or two in RODI water or freshly mixed saltwater and I have struggled with Phosphate levels.
My Red Sea cube tank, which has a high Bioload, I feed about 1/3 to 1/2 cube of mysis or brine per day. I have some pellets too that I feed on occasion to mix it up (around a pinch full maybe 20-30 of New Life Spectrum Thera A Regular). I only do one feeding per day and use pipette to slowly feed the fish.
My 25 Gallon Lagoon (I have 5 total fish) I have been able to keep phosphates pretty stable now around 0.1 which I am happy with. I feed around 1/3 of a frozen cube but I feed bloodworms, frozen Cyclopods, Brine, & Mysis (not 1/3 of each but a small chunk of 2 of the bunch). I usually choose two and then do four feedings per day totaling a 3rd. I also mix in some TDO B2 pellets as my Mandarin eats bloodworms & cyclopods for sure. But he definitely eats TDO B2 pellets.
I plan to order the Plank auto feeder and completely shift over to TDO B2 Pellets & I will probably feed 7-8 times per day in small bursts. If anyone uses a Plank currently I would be curious how long you feed & what you feed out of it!