Why don't my plants grow well?

[martinmin]

My big tank is 75 gallons, and almost 4 months now. As of today, I tested:

TDS: 250

GH: 200 (AC test strip)

KH: 80 (AC test strip)

Those values look good to me and now I am doing water change  about every 2-3 weeks. The problem is that my plants don't grow well. Please see the pictures. They don't grow high, and the leaves look very old, not new. The substrate is new.

Should I start to add liquid fertilizers into it? My friend has a similar tank and the plants in that tank grow really well. They look new, and grow tall, much more vibrant than my tank. 

Edited August 13, 2023 by martinmin

[lefty o]

if you havent added any fertilizer, id probably start. they are probably lacking a few nutrients.

[martinmin]

On 8/12/2023 at 6:03 PM, lefty o said:

if you havent added any fertilizer, id probably start. they are probably lacking a few nutrients.

Since it is new tank, I want to avoid adding fertilizers and see whether they can do well. I will add if I have to.

[Scapexghost]

Test nitrate. Considering increasing light intensity and/or duration

[martinmin]

I just added AC all in one fertilizer and then tested. Nitrate about 5-10, pH about 68-70.

Seems perfect?

I also added 3 more hours of lighting, from 8 to 11 hours. See how it helps.

[Alex S.]

On 8/12/2023 at 10:00 PM, martinmin said:

I just added AC all in one fertilizer and then tested. Nitrate about 5-10, pH about 68-70.

Seems perfect?

I also added 3 more hours of lighting, from 8 to 11 hours. See how it helps.

What are your ammonia and nitrite levels? 

[Galabar]

Root tabs might also help the new soil.  Just give it fertilizer, light, and time. 🙂

 

[RennjiDK]

On 8/12/2023 at 9:08 PM, martinmin said:

Since it is new tank, I want to avoid adding fertilizers and see whether they can do well. I will add if I have to.

You can't grow plants without feeding plants.

[martinmin]

On 8/12/2023 at 7:09 PM, Alex S. said:

What are your ammonia and nitrite levels? 

I didn't test them, but they should be 0, since I used to have fishes in it and they live well, although I had taken them all out.

On 8/12/2023 at 10:31 PM, RennjiDK said:

You can't grow plants without feeding plants.

So adding fertilizers is a common practice into fish tanks? I thought the ecosystem can sustain themselves without usinging additional fertilization. 

[lefty o]

On 8/13/2023 at 1:42 AM, martinmin said:

I didn't test them, but they should be 0, since I used to have fishes in it and they live well, although I had taken them all out.

So adding fertilizers is a common practice into fish tanks? I thought the ecosystem can sustain themselves without usinging additional fertilization. 

sometimes with fish poop, and food that can give plants many of the nutrients they need, but even with that plants need to be fed.

[mynameisnobody]

What is the stocking? 

[Shadow]

Yea as @mynameisnobody how heavily is it stocked? If its not very stocked you'd not have enough nutrients to sustain that many plants. Definitely add nutrients like the ACO Easy Green and whereas increasing light is ok, I would watch it...especially your blues...as you can get a algae bloom if the blue spectrum is high combined with too much light time. You could prob increase your time a bit and even give a mid day break if you want the light on longer. Something @nabokovfan87 taught me. 🙂 

[Alex S.]

On 8/13/2023 at 2:42 AM, martinmin said:

I didn't test them, but they should be 0, since I used to have fishes in it and they live well, although I had taken them all out.

So adding fertilizers is a common practice into fish tanks? I thought the ecosystem can sustain themselves without usinging additional fertilization. 

I would say you’re probably good to add fertilizer. It sounds like you’ve got enough beneficial bacteria to keep up with everything. I know with easy green specifically, they suggest dosing until you have nitrates between 20 and 50 ppm. I’m still pretty new to keeping plants, so I would definitely listen to other opinions, but from my research I would say you have plenty of room with your nitrates to dose a bit of fertilizer. Especially with the plant load you have in that tank, I think you are probably gonna need more nitrates than what you have in order to feed them.

[PineSong]

The good news is that if you have fish in the tank, fish waste will accumulate over time and feed your plants. The less-good news is that depending on what size and number of fish you had in there, 4 months probably did not add enough fish waste to get you past the starting point with stem plants.

If you are putting new plants (with small root systems because they are new) in a tank without any nutrients (because your tank does not have an accumulation of fish waste to equal sufficient fertilizer) there is literally no way for those plants to access the resources they need to promote growth. 

In addition to fertilizing, it will help your stem plants grow taller and thicker if you prune them regularly, especially in the beginning. Cutting them down by half their height every few weeks will help give them a chance to develop root systems large enough to support new growth, and cutting them stimulates new growth.

Here's a video that may be helpful:

 

 

[RennjiDK]

On 8/13/2023 at 9:30 AM, Shadow said:

Yea as @mynameisnobody how heavily is it stocked? If its not very stocked you'd not have enough nutrients to sustain that many plants.

Livestock only add nitrate and phosphate. Even then, it entirely depends on the feeding schedule. Planning ferts around stocking is not a road to success.

On 8/13/2023 at 9:30 AM, Shadow said:

Definitely add nutrients like the ACO Easy Green and whereas increasing light is ok, I would watch it...especially your blues...as you can get a algae bloom if the blue spectrum is high combined with too much light time. You could prob increase your time a bit and even give a mid day break if you want the light on longer. Something @nabokovfan87 taught me. 🙂 

If blue light was responsible for algae, every reef tank on the planet would be a wall to wall display of Mt Dew.

[lefty o]

On 8/16/2023 at 12:52 AM, RennjiDK said:

Livestock only add nitrate and phosphate. Even then, it entirely depends on the feeding schedule. Planning ferts around stocking is not a road to success.

If blue light was responsible for algae, every reef tank on the planet would be a wall to wall display of Mt Dew.

in freshwater, blue light plays a large part in algae. FW-REEF= not the same. 

[RennjiDK]

On 8/16/2023 at 9:30 AM, lefty o said:

in freshwater, blue light plays a large part in algae. FW-REEF= not the same. 

They're the exact same. What makes you believe that GHA, GSA, BSA, etc, photosynthesize using a different spectrum in the presence of salt?

[lefty o]

the plants are different, the composition of the water is different. an entirely different animals.