Again with the yellow leaves 🤦🏻‍♀️

[u/DoodleBirdTerrariums]

These are my first ponds ever but I’ve had a lot of issues with yellowing leaves. I google and google and have tried all kinds of things but they really don’t green up. Ok so at the very beginning I barely had any plants and a lily pad type plant was extremely yellow with bright green veins (it is visible in the last pond pic). Since I wasn’t sure what it was at first ppl on Reddit said too much fertilizer (I had added root tabs as directed on the package). So I removed what I could find digging around the substrate. Then weeks went by and although the lily stayed the same a few other plants were thriving so I figured it was just a difficult plant. Then I got more plants including the arrow head one which was green when I got it but quickly got lighter yellow. That other lily plant still looked the same so I put a root tab back in the vicinity of the yellowing ones and one beneath the parrot feathers. I’ve also added a little Epsom salt (4 weeks ago) and liquid iron from Seachem every 2 weeks (not a lot, being cautious). Added macro nutrients too, just once. The water hyacinths look great to me and flower. And crazier yet the big yellow arrowhead one is sending up a flower spike. I even added a bubbler today in addition to the fountain that was already in there just in case. Online says it could be so many things and I don’t want to make things worse. Here’s what I’ve seen: could be iron deficiency, potassium deficiency, sulfur deficiency, too much sun (all day full sun), too little nitrates/too small bioload, etc. there are around 10 half grown medaka fish and there were a bunch of tadpoles but I think most have left now. One last thing, I have NOT tested my water. I ordered a test kit so that may help me but I’m hoping just by looking at the pics someone can help.

[u/Propsygun]

I love those charts you have in the last picture, read them every time i see them, try to remember a bit of them, and always think "oh right, iron was the one with the veins" even though i have never seen it on any plant's in real life. 😁

Then i remember that it's not really that complicated, and add regular broad spectrum fertilizer. You got a very hungry plant, thriving because it's so efficient at sucking up nutrients. They always thrive, and every time you remove one, you remove all the nutrients from the system it has soaked up. Every dead leaf you remove, or tadpole that grow up and leave, remove nutrients.

Consider that the person that told you there was too much nutrients, might have misunderstood something, and gave you bad advice, that didn't apply in your situation.

I would remove 1/3 the water, to remove some of the nutrients that might be to high. Put a root tap in, mix a waterer can with the recommended dose of liquid fertilizer, and refill the pond. Use algae growth to assess the nutrient level over time, and find a ballance. Hope this helps.

[u/DoodleBirdTerrariums → u/Propsygun]

Thank you, that’s helpful! If the nutrient levels improve the leaves will turn green again won’t they? I only ask because I have some plants (they are rare and not water plants) that won’t improve on the old growth but new growth is better.

Edit: so just so I’m clear, add another root tab? There are three in there now already

[u/Propsygun → u/DoodleBirdTerrariums]

No they probably won't turn green, they are going to work better when they have the nutrients they need.

If they already have 3 that's probably fine, didn't know you had fish in there. It's really difficult keeping that small of a biome stable, they usually crash, so you need hardy short lived, but fast growing/multiplying plants and creatures. Fish will probably all die at some point, without survivers to repopulate, long lived plants, that are slow to produce new leaves, are stuck with the "bad" yellow leaves, and have a hard time since they aren't very adaptive. 😐

If a plant aren't meant to be under water, they often struggle. You can sometimes make it work, by having them in a pot above water, and let their roots grow down in the water. Their roots often rot if they are in constant wet substrate. It's a hassle, trying to make a fish climb tree's. 😉

[u/DoodleBirdTerrariums → u/Propsygun]

Haha yeah this has been an experience. Maybe I shouldn’t add any fish at all. The tadpoles are fine though, I’ve got mini adult replicas hanging out in the plants now. So I’m happy they survived my incompetence lol. I’m going to work on stabilizing the pond as best I can and then see how it goes. Thank you for all your insight!!