It seems that we have made some progress here. But, just to recap and to make sure I have this right.
- For your project, all your solenoids and pumps require 12V which you will supply with a single 150W 12V power supply.
- In addition, you need to power your Photon and that will require a 5V buck regulator (linear or switched, your choice) to reduce the 12V down to 5V.
- We agreed that any of the components that draw more than 2A would need to move to a soldered breadboard and those circuits would need solid core wire to carry the higher-current.
I would suggest you move your entire project to the soldered board if you intend to leave it in operation for any significant amount of time. I would also suggest you use consistent colored wires and try to be neat to make troubleshooting and future improvements easier.
As for the weird behavior, I think you need to troubleshoot this in a methodical manner. The first step is to isolate the systems and validate them individually such as the MOSFET circuit and the Photon control lines. Ideally, you can confirm that each is working correctly before you connect them. Then, if you are getting an unexpected result, you may need to make some measurements of what is happening in your circuit. For example, if you could measure the Photon pin that is controlling the MOSFET, you could validate it is delivering the right signals. An oscilloscope is ideal for this as some issues are transient in nature and may not show up on a volt meter.
Sometimes a circuit simulation is helpful. Here is one I created for this circuit (you will need to use Chrome to open this link)
Can you try to collect some more data and let us know what you find?