Mitch Varela

And check it after an unplanned reboot specifically. Everything looks perfect until the power blips, then the machine boots with last known time and half your schedule slides.

Do not rule out power just because the CPU stays up. Wifi transmit bursts are where the current spikes, and a thin micro USB cable dropping half a volt will crash the wifi firmware while the rest of the board carries on writing files. That matches your symptom better than most software explanations. Try a short thick cable and a supply you trust before you go deeper.

Twice a day misting at 80 percent with a fresh tank and no animal is probably more water than you need. You can back off to once a day, or once every other day, and let the substrate handle the humidity. Constant surface wetness on the wood feeds exactly what you are seeing, and cresteds do better with a proper wet and dry cycle than with permanently damp.

Alkaline in a cold garage is a bad time generally. I switched every outdoor and garage sensor to lithium two winters ago and the mystery dropouts stopped even where I never changed anything else.

Stop booting from the card. A Pi 4 with an updated bootloader EEPROM boots straight off USB, and a 120GB SATA SSD in a cheap USB3 enclosure costs about what two more decent cards cost. That one change ends this for almost everyone running an always-on service.

If you want to keep the card for now, do two things. Move logging to RAM (log2ram, or just point rsyslog at a tmpfs) and turn Pi-hole's query logging down or off. A DNS sinkhole writes constantly, and consumer cards have tiny controllers doing very little wear levelling once the partition is mostly full.

Also run vcgencmd get_throttled next time it goes read-only. If that comes back as anything other than throttled=0x0, the card is a victim rather than the cause.

Also check where the water goes when you mist. If the front glass gets the spray and the back corner has been dry for weeks, the population concentrates somewhere you never look. Mine live almost entirely under one piece of wood at the damp end and the rest of the tank looks empty.

The drive is too much, and the number confirms it. 0x50005 decodes as under-voltage happening right now, arm frequency capped right now, and both of those having occurred at some point since boot.

A 2.5 inch spinning disk pulls somewhere around 800mA to 1A for the second or two it takes to get the platter up to speed, on top of whatever the Pi is doing. The Pi's USB ports are budgeted for about 1.2A total across all four, and the official supply has no headroom left for a surprise. Options in the order I like them: swap the spinning disk for a 2.5 inch SSD which idles under 300mA, or put the drive on a powered USB3 hub with its own supply, or use a Y cable so the drive draws from a separate charger.

If you leave it as is you will eventually get filesystem damage on the drive, not just a warning icon.

False bottom, for exactly the reason you flagged.

Two bags of LECA plus the water it holds plus three inches of wet substrate on top adds up fast, and an ordinary cabinet under a tall tank is already carrying a lot. Egg crate on PVC pipe legs with a layer of window screen over the top weighs almost nothing, gives you more usable water volume in less height, and costs a third of what the LECA does.

Build notes from doing several:

• cut the egg crate slightly undersize so it does not bind against the silicone in the corners
• use short lengths of PVC pipe as legs, one every 15cm or so, which is far more than you need but the crate sags under wet substrate otherwise
• fine window screen over the top, not weed fabric, which clogs
• put a length of pipe vertically in one back corner down to the false bottom so you can drop a siphon or a turkey baster in without digging up the tank

That last one is the thing people forget and regret. In a 36 inch tall tank you cannot easily reach the bottom to drain it once it is planted.

One thing worth checking on those cases: the thermal pad. They usually ship with a couple of blue pads and people either forget one or leave the plastic film on one side. If the pad over the main chip is not making contact you get a case that is cool to the touch and a chip that is hot, which is the opposite of what you want. If the whole case feels warm, contact is good.