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Fluval Flex 15 build, with DIY ADA-style stand and ESP32 Reef Controller

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Hi all,


This is my second foray into reefing after a nano reef a few years ago I had to shut down when I moved to University. 


Now that I am settled in a bit more though, I wanted to take a second crack at things and put to use some of the engineering upskilling I've done since.




  • Fluval Flex 15 (57L)
  • Stock return pump (will either upgrade this, or add a wavemaker)
  • DIY laser cut media box (running floss, carbon and PhosGuard probably) 
  • AquaKnight Nano LED A029 v2 (link, which I immediately voided the warranty and hacked so I could PWM the channels manually)
  • DIY ADA-inspired stand
  • ESP32 Reef Controller, which I'm calling the Reef32 (currently controls light profiles, ATO and measures temperature. Eventually will do AWC and maybe pH although am not sold on if this is needed) 




Managed to get a full sheet of 18mm poplar core plywood from a local plywood shop for just NZ$50 (~$US30) after pleading poverty as a student. Cut it to shape without much of a plan, just dimensions in my head using a skillsaw. Turns out your meant to use a special plywood blade to get nice cuts, so my cuts ended up all over the place. This is the initial box I got out of it:




Because of how messed up the cuts were, I used the sheet pretty inefficiently so all the facing edges were factory edges. Still was pretty unhappy with the result and had given up at this point and was looking for a stand to buy...


But after looking at it for a couple of days decided it was probably worth a look seeing what it looked like with a cabinet door. It only would be another half hour anyway.




You can kind of see how the door didn't really sit square, but decided after some sanding and a stain on the edges it'd come out pretty nice. 




And the insides, with some equipment installed plus an ATO reservoir. The reservoir is 10L RO/DI water bottle I can buy at the local supermarket. I'll fit the ATO pump to the lid so I can swap them really easily. 







I originally ordered one of those Hipargeo lights off of fish-street.com, but they sent me the v2 model because apparently the Hipargeo is not being manufactured anymore. Was a bit annoyed because I explicitly knew that I'd be able to hack the original to get a PWM line and control the lights myself, plus the original didn't have a timer so there was actually a good reason to get a PWM out line. The v2 however does have a timer, but I already had my heart set on building a web interface for it so open goes the case.






Pretty simple design with one PCB having just the LED chip (and a thermistor) and the other containing all the logic and driver circuitry. The ribbon cable between the two has all three channels +/- (and thermistor +/-). 




The three inductors on the left (the grey things with 470 on them) are a component of the three LED channel drivers. They use a PT4119 IC (couldn't find much on them, Chinese chip with no english datasheet. Google Translate to the rescue though... turns out they all have a DIM pin which was connected to an STM microcontroller. I cut the traces connected to the microcontroller (RIP warranty) and added wires to all three DIM pins. According to the datasheet they a 5v PWM single, and cut off at 2.5v (although I haven't observed this happening they seem to work all the way down to 0.5v) 




Wires added, and trace cut (see where the PCB looks all scratched down the bottom left)




Put it back together and neatly ran the wire out. Basically looks professional. Checked the PWM with an Arduino Mega and it works a treat! Was a bit of a heartbreaking moment when I forgot to attach a ground and I thought I'd permanently destroyed my light.



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Everything looks great, the only thing I would advise is not using phosguard regularly. It's a media that is best used on a need to basis with monitoring of levels.


It can easily strip a tank and 0 phos and 0 nitrates is not beneficial

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