I built one 8-10 years ago using small peristaltic pump heads. I forgot if I posted it here - I was fairly active when I was building my 5’ 180G tank which was one of the earlier high light LED / custom driver / controller. I used a fairly simple timer to control the dosing though. It worked well enough to keep the tank stable while I travelled 2-3 weeks for work many times.
I’ll see what I can find. I stole ideas from Reef Central posts if I recall.
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