Who Gives A Fish Forums

Terrafox wrote: ↑Thu Apr 03, 2025 6:05 am I had a similar issue in my 65-gallon tank recently, and it boiled down to water flow. The fertilizer nutrients just weren't being circulated effectively around the plants.

I've since adjusted the setup - the filter outlet is now a spray bar, and I've added a power head just beneath the water's surface, directing the flow parallel to the surface, from back to front. This creates a circulation pattern where the water flows down the front glass, along the substrate, and then back up the rear glass, where there's a low-pressure area. This change has largely resolved my issue, and my plants are now growing much better.

What substrate tabs are you using now - I may have some insight on that. Also, I didn't catch the GH of your source or tank water.

You mentioned having a powerhead in the past, but it was too strong for your fish and you were concerned about breaking the surface and losing CO2. I can see why you'd think that, but strong currents aren't ideal for Echinodorus, and they can actually move nutrients past the plant's leaves before they can be absorbed. I've had some experience with this myself - I lost a couple of plants due to strong currents from my canister filter, but moving them to a different spot helped them recover.

Regarding surface disturbance, it's a bit of a debated topic these days. While it's true that more vigorous disturbance can increase gas exchange, I aim for some gentle rippling at the filter return, just not excessive and confined to a small area. You're working with low-tech methods, and that's what I use too - high-tech is a whole different story.

As for injecting CO2, I don't think that's the answer. There's usually enough CO2 produced by decomposition in the substrate to get the job done. However, your 10-hour light cycle is likely too long and needs to be balanced. Try reducing it to 8 hours, and be prepared to go down to 7 hours if needed. It takes a couple of weeks for changes to become noticeable, so be patient.

To give you an idea of what I'm suggesting, I've had success with moderate light on 7 hours, using Flourish Tabs next to my larger swords and replacing them every 3 months. I also dose Flourish Comprehensive Supplement once a week, on the day after my water change, at the recommended single dose level. No CO2 needed.

I completely agree that high tech and low tech tanks have different requirements, and I wasn't suggesting that a low tech tank needs the same level of flow as my tank. My point was simply that high flow and surface movement aren't inherently detrimental to plants or fish. That being said, I do think it's crucial to have sufficient flow in a low tech tank to ensure even nutrient and CO2 distribution. And, of course, some movement at the water's surface is also important for overall tank health.

Ultimately, the key to success with a planted tank is finding that delicate balance between lighting, CO2, and fertilizers.

Terrafox wrote: ↑Thu Apr 03, 2025 6:05 am I had a similar issue in my 65-gallon tank recently, and it boiled down to water flow. The fertilizer nutrients just weren't being circulated effectively around the plants.

I've since adjusted the setup - the filter outlet is now a spray bar, and I've added a power head just beneath the water's surface, directing the flow parallel to the surface, from back to front. This creates a circulation pattern where the water flows down the front glass, along the substrate, and then back up the rear glass, where there's a low-pressure area. This change has largely resolved my issue, and my plants are now growing much better.

When a leaf dies right after a new one grows, it's often because the plant is removing nutrients from the old leaf to ensure the new one develops fully, which can kill the old leaf. Fortunately, a plant can only move around 7 nutrients: nitrogen, potassium, magnesium, phosphate, chlorine (in the form of a non-toxic chloride salt), and molybdenum.

I think a magnesium deficiency is often the culprit in these cases. Your answers to the questions above would really help determine the best way to resolve this.

Other issues that might be present are that the pH and KH value can reduce the effectiveness of your fertilizer. Calcium is often not in fertilizers, and sometimes it's an issue. Many manufacturers don't provide enough copper and zinc because they assume your home's water pipes will provide enough, but if you have a home with plastic water pipes or you use RO water, you might not have enough.

In most tanks without a CO2 system, you actually want more surface agitation to help mix air with water and drive CO2 into the water. CO2 has no effect on a mobile nutrient deficiency.

If you have a minor nutrient deficiency, reducing light intensity will slow plant growth and reduce nutrient consumption. This can help prevent running out of nutrients between water changes. But I think your nutrient deficiency is probably severe enough that lighting changes won't make much of a difference. Still, it wouldn't hurt to try.

Also, keep in mind that some plants don't grow tall when they get enough light. But if you don't have enough light, they will grow tall as they try to get more light. However, for that to happen, you need good plant growth, which you don't have in your tank.

Seachem fertilizer is different from Thrive but has some similarities, so I'm not surprised it didn't work. In fact, I tried four different fertilizers in my tank and all failed to provide good plant growth. After years of trying, I finally decided I had to make my own fertilizer. But I was reluctant to do it because it can be difficult to get right. I was right, it is difficult, but my first batch of fertilizer, as imperfect as it was, was vastly better than the four others I had purchased.

I've been doing a 30% water change every 10 days, and for the Thrive, I follow the bottle instructions, which is 1 ml per 5 gallons, usually once a week. My tank's well cycled, so ammonia and nitrite stay at 0, and nitrate's around 25-30 before the water change. pH's 7.5, but I don't have a way to check KH and GH, although I could take it to the LFS if needed.

I use tap water with a pH of 7.5, and it has a small amount of ammonia, but I dose Prime to neutralize it, and the system takes care of it quickly. I'm just really confused about what to do next, as I feel like I've tried everything over the past 2 years and still haven't seen any progress. The plants look healthy to me, but they just won't grow upwards. I don't get why they generate new leaves but stay low.

I've tried playing around with light intensity, but it feels like a waste of time, and it's not likely to fix anything. It might even make things worse. I'm currently using Osmocote root tabs in gelatin capsules in the substrate. Would you recommend switching to a pure root tab, or is that not worth it either? What are some reasons a plant would generate new leaves but not grow upwards? I just don't understand it.

To start off, I've got a few questions - what are the dimensions of your tank, and what kind of lighting setup are you using, along with the wattage?

I think one possible solution could be to remove the Anubias, as it's essentially a garden plant, and it might be taking up valuable resources that your swords could be using. Swordplants tend to produce smaller leaves when they're not getting enough light or nutrients.

With your current fertilization schedule, it's likely that the nutrients are being depleted within a few days, especially with all the plants you have in the tank. When you add more fertilizer a week later, the plants just suck it all up again, leaving the tank nutrient-deficient for the rest of the time.

You might want to consider monitoring the nutrient levels in the water, and adding fertilizer when the levels start to drop. This could be anywhere from several times a week to every few weeks, depending on how many plants you have in the tank. More plants means more fertilizer needed, and also more light, since they can shade each other out.

If you can't test the water for nutrients like iron, doing a large (75%) water change before adding more fertilizer could help. This way, you dilute any remaining nutrients and avoid an excess of certain nutrients. You could try doing a big water change twice a week, and adding fertilizer after each change to see if that helps.

Terrafox wrote: ↑Thu Apr 03, 2025 6:05 am I had a similar issue in my 65-gallon tank recently, and it boiled down to water flow. The fertilizer nutrients just weren't being circulated effectively around the plants.

I've since adjusted the setup - the filter outlet is now a spray bar, and I've added a power head just beneath the water's surface, directing the flow parallel to the surface, from back to front. This creates a circulation pattern where the water flows down the front glass, along the substrate, and then back up the rear glass, where there's a low-pressure area. This change has largely resolved my issue, and my plants are now growing much better.

I think there's an issue with the osmocote root tabs you're using. They're designed for terrestrial plants, not aquatic ones, and have a different nutrient requirement. High nitrate and phosphorus levels are a problem. I know some people use them and say they're okay, but that doesn't mean they're safe or effective.

Your nitrate levels are higher than they should be, around 25-30 ppm before the water change. This is a sign of a problem. Nitrate should be as low as possible in a tank with fish, and it shouldn't vary. Most aquatic plants don't take up nitrate in a low-tech tank with fish, so adding it with the osmocote is pointless. It's also negatively impacting the biological system and your fish.