I know this is a necro post, but I am having this exact issue. Blue mode is brighter, red is dimmer.
But I noted another thing. I have the 59W model. Stock PSU pulling ~70W. My Mean well LRS75 is pulling 70 as well.
When I hooked it up to my TC421 it's pulling 86-88W, which is insanely over the rated fixture wattage. I think I'm gonna ditch this whole idea and go back to stock, I'd rather not have to purchase a new light.
Are you feeding the TC-421 off the same circuit you are measuring?
It pulls "some" wattage though not sure how much atm. The wifi contributes some more than the plain tc-420
I assume the internal MOSFETS are "lossy" as well.
Can't say if 16-18W is "normal" TC losses though but it seems high.
Your lucky day sort of..just was playing w/ my tc-420.
On idle it pulls about 1W
0.1A at 9v
One thing though the TC can't add watts to the light , well not in the normal circuit AFAICT.
If yo have a VOM measure the current to the light head in series, voltage across the light. will get you the real power.
Fluval, nicely, only includes the diode wattages (not even sure if they factor in resistor losses here) and not power supply wattages plus light head as you have seen.
If your meanwell has a voltage adjustment you can always drop the voltage a bit.