Disaster Strikes: The autodoser incident

Sooner or later it will happen to you. Something will go awry and turn your beautiful aqua eco system into a nightmare scenario for your fish, and maybe your whole house.

I was lucky that this wasn’t one of those incidents that required some kind of insurance claim. Some of the inhabitants of my planted 60 gallon aquarium, they weren’t quite so lucky.

I’ve been using a DIY fertilizer dosing setup successfully for some time now.  But, recently, I tore the setup down to rearrange it and top off the liquid fertilizer.  I moved the dosing pump to the outside of the tank near the water line.

After a bunch of testing and re-testing I finally got the system to prime and flow like I wanted. That night I headed off to bed and awoke to the horrifying noise of an air pump running in my cabinet.

The only air pump I have set up in my 60 gallon fish tank is the one used to keep the fertilizer mixed, and it only runs for 5 minutes while the lifter pump is running – at 10 PM.  Here it was 7AM, the 1 liter bottle of fertilizer was nearly empty and the water column had a distinctively tannic look to it.

Then the panic set in.

I quickly performed a 50% water change and unplugged the system. Some of the fish were at the top of the tank, but many of the livestock didn’t seem too bothered by the rich environment.

Later in the day, things weren’t so good.  I saw the ottos were lethargic and looking rough, and there was a dead white cloud minnow on the bottom of the tank.  I transferred the ottos to another tank and did another 50% change

I’ll probably keep doing at least 20% changes regularly this week to make sure all the excess nutrients have been removed, and hope no more fish succumb to the water quality.  One of the ottos sadly did not make it through the night.

I did a post-mortem and found that the timer I use for the dosing system has two on/off settings.  Somehow, I accidentally enabled the second on timer without enabling an off timer.  Essentially the system was programmed to come on at midnight and never turn off.

The takeaway from this is when setting up your equipment, double check everything.  Make sure it works as intended.  Take your time, the results of this simple mistake could have cost me my entire population.  While this was a DIY setup, the same can be said about commercial products as well.

I’m just lucky this didn’t happen with an overflow system or something like that.  It doesn’t take much water leaking to ruin a floor or more.

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