Catappa leaves: watch for pH drop

[Fish Folk]

Found a dead Colombian tetra in an established tank last week, and another today. Because we had recently added them, left off being overly concerned with the first death. Mistake! 
 

Before doing a water change, I tested the water. Point of reference: water from our tap is 7.8-8.0 pH, but on the soft-side. That means there is not a lot of hardness to buffer the water and protect from pH swings — one reason why we’ve not ever really gotten into CO2.

 

So, tested Ammonia... Nitrite... and Nitrate... Ammonia and Nitrite were fine. Nitrate was up (ca. 40 ppm) meaning definitely time for a water change. However that’s not unreasonably high. One more test... pH... 6.0 😬

 

Best I can figure, we added a lot of oak leaf litter, wood, and alder cones to the tank — and recently, several full sized Catappa leaves (Indian almond leaves). 

What happens is that the biological breakdown of those leaves releases large amounts of humic acid. 
 

So! Though Catappa leaves are fantastic for releasing healthy tannins... they can easily negatively contribute to a pH crash — especially if you have softer water.

Edited November 30, 2020 by Fish Folk

[KBOzzie59]

"Alder cones can lower the pH of the aquarium which in turn not only stimulate the breeding of some fish but also act as an anti-fungal agent and elevates the hatching rate of fish eggs in certain species. Effects of pH rely on the hardness of the water, the harder the water the lower the effect on pH."

"catappa have shown some effectiveness against some bacteria, specifically, Plasmodium, and some parasites as well. When Indian Almond leaves are immersed in water, the tannins and humic substances are released, which can lower the pH of the water." (same as alder cones, the softer the water the more dramatic the drop)

[Fish Folk]

True! Quote source?

[KBOzzie59]

Google...

But here.

Indian Almond Leaves: Keeping your fish happy, naturally.

FISHLAB.COM

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Important: Adding indian almond leaves to your aquarium without reading this guide first could kill your fish! Click here!

 

Alder cones - How alder cones affect pH and color in aquarium water

WWW.ALDERCONES.COM

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How alder cones affect pH and color in aquarium. Test showing how pH gets lower and color of water chenges by alder cones.

 

[Fish Folk]

Good tips. Thanks. Yeah . . . we found that both alder cones and catappa leaves generally do help. But in this case, the pH crash _appears_ to have been too much. No sign of other sickness on the Tetras. If more die, then perhaps it's something sneaky. But knowing how fast pH can drop when water is soft is an important learning step! Always learning . . .

Edited November 30, 2020 by Fish Folk

[Kirsten]

Wow that's quite the drop, even for soft water! I regularly dose my 10g betta tank with 3 to 6 mini catappa leaves (about as much as one half or full-size leaf) once a week or two and usually only see 0.1-0.2 drop in pH. I suspect that oak leaf litter dumped a ton of tannins in there too on top of all of that. Goes to show that you should definitely make pH adjustments very incrementally.

[Fish Folk]

Yeah. Lesson learned!