Backyard Aquaponics
A place to discuss aquaponics

Yeah, I did. There was some very slight foaming before I washed the sand and none after. However, I think there's likely some calcium that's still hanging around and slowly raising the pH.

Behold! A germinated arugula seed... two days after planting.

Lost 2 fish in the last couple of days. Water tests appear okay There are areas that look pink on both fish - disease? Or symptom of something else?

(Sam, do you think these are Mojarra?)

Looks like skin lesions which can be caused by a variety of things (bacteria, fungus, etc). Water quality is first suspect (DO, temp, alkalinity, ammonia, etc.) and any major fluctuations that might have resulted in stress (large temp swings, pH swings, DO swings, etc.

You may want to consider salting your tank to help reduce the stress and increase slime coat production (which can protect the fish from further intrusions on their skin).

Thanks Eddie. They had a bit of a stressful journey from their source to the tank, and the pH of my tank was unexpectedly high (I hadn't measured it for a while) when they were added. So I'm guessing stress induced, as you suggest. I have another fish that is not looking great today so I separated it out and added salt to its quarantine tank.

The seeds I sowed directly in the system are all sprouting remarkably well. However, a few of them are have yellow borders on the cotyledons. Especially visible on the cucumber and bok choi (see photos). The cucumber is at the far end of the system (driest) so I don't suspect over-watering. Any ideas?

Most likely a potassium deficiency...

Thanks Eddie. Perhaps all my nutrients are low since the water pH is still hovering around 8 to 8.2. Hopefully this will drop in a week or so. Will continue to monitor.

Also, if my fish are Amphilophus alfari, EOL (http://eol.org/pages/215976/details) suggests that they prefer a slightly acidic environment so the pH of 8+ might also be stressing them out. Here a photo of Amphilophus alfari: https://www.monsterfishkeepers.com/foru ... pg.981720/

Neat looking fish... Is your source water in the 8s as well for pH? Adding rain water?

Looks most like potassium but iron is also a possibility since the pH is high.

If those are the same fish, what will you feed them? Also were they wild caught? beautiful fish though, well I mean the live ones, lol

Eddie, the source water is rainwater which is fairly acidic. The bottom line is that I think my sand has some buffers that are raising the pH over time - despite a negative vinegar test on the washed sand.

Scotty, what do you make of the change from yesterday to today in the cucumber? Colour me surprised!

I embarrassed to say that I don't have much info on the feed the store gave me. It's a pelleted feed that they recommended (just a small bag to get started) until I source something more substantial and er, labeled with ingredients/specifications. The fish are from a local river but I don't know how long they were in the store. A few weeks, I would imagine.

Here's a chili pepper that's apparently loving the sand bed (see chili in center).