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JBL CO2 kit

Swap M502 for M503?

  • Yes

    Votes: 0 0.0%
  • No

    Votes: 0 0.0%

  • Total voters


New Member
30 Jun 2020
Stockport, Greater Manchester
Hello boys and girls.

I hope everyone is fine and dandy?

I bring to you a question that i feel only experience can answer.

I have just spent 1000s on a new tank and all the hardware and part of this kit was the JBL PROFLORA m502:
Package contents: refillable 500g CO2 cylinder, fitting, stand, pressure reducer, night switch-off (time switch sold separately), diffuser, bubble counter, 3 m hose, backflow stop, CO2/pH test, liquid fertiliser & daily fertiliser.

I also bought the inline diffuser - JBL PROFLORA Direct

I went back to the LFS yesterday for some more bits to get the system off the ground and it was suggested that i get the M503 instead, they are willing to take back the used M502 and swap it over (paying the difference).

Can anyone please offer any thoughts on this?

I cant get the money back on my M502 so its either i keep that OR upgrade to the M503 that comes with the computer:
  • Promotes plant growth and leads to lively fish: measurement and control computer with touchpad for the high-precision calculation and control of the best pH value in aquariums
  • Connect sensors (pH sensor not included), set desired values in menu, connect with solenoid valve (not included)
  • Digital measurement and control technology: graphic display, direct user interface, separate sensors for pH value and temperature
  • Compares desired and actual pH value and controls the CO2 supply with solenoid valve (not included)
  • Package contents: CO2 controller with touch display; incl. wall mount, power supply unit, temperature sensor with 2 suction cups and connection cable for the solenoid valve, cuvette holders for calibration liquids
It sounds like a good idea to be fair, the automatic control of CO2... after just 24 hours of trying to get this 502 working, haha,

As a side note, Can i use the JBL kit to work with a fire extinguisher?


6 Apr 2017
How much are they charging for the M503. AFAIK, it does come with solenoid valve (attached to the regulator). Personally, I’d stick with what you have.

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