I've been playing around with hydroponic control systems for quite some time now and I'm still encountering unique and old failure modes. It's fasinating. Always new failure modes to discover.

This week's was a doozy. First, I noticed that the system was dosing EC frequently even though the EC was at above minimum threshold.

Looking at the minimum EC on the graphs and the logs. We can see 2 problems.

1) We are getting errors coming through as valid sensor readings.
2) We're making dosing decisions based on a single value.

I discovered these things remotely and started cooking up an appropriate firmware update.

I was curious about how the system hadn't had any of these errors previously and suddenly was getting loads of errors. Something had changed.

When I investigated the system, it was obvious. Recently, I had installed a separate tank depth sensor and double-sided taped it's micro controller to the lid of the enclosure. It had fallen down and shorted the atlas scientific dissolved oxygen module. A short to ground had switched it to you UART mode which was causing chaos on the i2c bus.

I've deployed the firmware fix and now I can use the a dissolved oxygen module to stress test the system before I fix the UART issue and get the dissolved oxygen module working which is still on the to do list.

There was a 2nd fail, a plumbing issue had caused nutrient A not to be dosing I'd pushed the pipe into the container too far during install, and it had gone up the other side so its level was almost at the top of the container.

Apparently, nutrient part B has far more effect on EC than part A.

And fail three, something had blocked the pluming to one of the trays so it was sitting full with water.

Anyway summer is comming and we are bound to see more fails as we go.