Too Much CO2? Rotala Macrandra Tips Not Looking Good

[Plants101]

Hi UKAPS,

I've been growing rotala macrandra in three separate tanks. Two of the tanks have some really good looking rotala macrandra. No stunting, twisting, or anything else weird. However, the last tank is causing some issue. Not too sure why.

Here's a picture of the good macrandra:


Here are pictures of the bad Macrandra:




Here's a few theories:

1) Too much CO2. The first macrandra has barely any CO2 going into it, and is lit with natural sunlight and a cheap NICREW LED. The second macrandra has a ton of CO2 going into it, and there are no fish in there because they are too uncomfortable in there due to the high amounts of CO2.

2) Lighting quality. Natural sunlight is often the best for growing plants and is high quality light. On the second tank, I'm using an SB Reef light with 20% Red and 20% Blue. Not sure about the quality of the light there because it really makes the colors look completely washed out.

I'm a bit confused because the macrandra is the only plant in all of my tanks that look subpar. Everything else is thriving, especially in the tank with super high CO2 level. I'm getting some pogostemon erectus with a nearly 4cm diameter and they're loving this tank.

Thank you all for your time and for any advice you can give.

 

[Simon Cole]

I'm guessing this is a pH problem. Obviously people are still going to need to know about your soil, fertiliser dosing, CO2 ppm, lighting schedule, water source, temp etc. But I'm happy to put money that the plants will recover if you reduce the CO2 (it causes acidification in excess).

 

[Plants101]

I'm guessing this is a pH problem. Obviously people are still going to need to know about your soil, fertiliser dosing, CO2 ppm, lighting schedule, water source, temp etc. But I'm happy to put money that the plants will recover if you reduce the CO2 (it causes acidification in excess).

Thanks for letting me know, I completely forgot to give all of the other info. My bad. Here it is:

Tap Water @21C
UNS Controsoil (Low ammonia aquasoil) buffers water to a low KH
Half of EI Dosing Regimen
Lights on for 7.5 hours, CO2 comes on one hour before lights come on

I think you're right about the pH being too low. I recently added some buce and some of the new buce leaves look like they're getting melted in a rather aggressive way. The leaves are perfectly formed (no stunting or anything on the buce), but they're melting like someone is burning holes through them.

 

[X3NiTH]

If you want to stop the Buce melt you will need to dose full EI micro, ensure there is a decent supply of Iron, Manganese, Zinc and Boron in the mix, the levels that halted Buce melt for me was Fe 0.15mg/L, Mn 0.05mg/L, Zn 0.04 mg/L and B 0.03mg/L every day until recovery and then you can back off to every second day and monitor the progress.

There were other things I did at the same time to save my Buce like increase the KH and GH Hardness, but in the long run I don't think that's all that necessary as long as there is some of each.

If you run out of Nitrate and Phosphate in the tank (from extending the time between water changes) the Buce won't really mind they'll just rob older leaves for the nutrients so mainly going pale and pinking up eventually leading to whitening of older leaves and then eventually older leaf excision, importantly though no holes and no melt. I'm not sure you can run out of Potassium in a Buce tank, I haven't tested for depletion yet but it's a transport molecule so it's passed in and out of the plant on a regular basis.

A supply of carbonates to replace any depletion would help keep the pH up a little higher, maybe add a little cuttlefish bone to allow that little extra buffering capacity.

 

[Witcher]

I've been growing rotala macrandra in three separate tanks.

What are the differences between those tanks apart from CO2 and light? And are these macrandras different in height in each of the tank?

My macrandra always had twisted leaves when I was experimenting with Mg, Ca and/or K (similar to A. reineckii) - when closer to the light source (in your case it can be light quality) it needed less of Mg (generally red plants need less of Mg and N) as it was converting from chlorophyll to carotenoid use for storing the energy coming from light.

 

[Plants101]

What are the differences between those tanks apart from CO2 and light? And are these macrandras different in height in each of the tank?

My macrandra always had twisted leaves when I was experimenting with Mg, Ca and/or K (similar to A. reineckii) - when closer to the light source (in your case it can be light quality) it needed less of Mg (generally red plants need less of Mg and N) as it was converting from chlorophyll to carotenoid use for storing the energy coming from light.

The light with the bad macrandra is the SB Reef light. I think it's putting about 120+ PAR down at the substrate level. The other tanks are getting natural sunlight.

I'm using a GH Booster and adding about 1dGH to my water after a water change. Is this an issue? The GH of my tap water is about 11 dGH

 

[Witcher]

Hey @Plants101 I think question is what is in that 1dGH and in your tap - how much Ca, Mg etc in relation to each other. What I can see in my tank is that R. macrandra without any doubts prefers softer water - I keep appr 3-4 dGh and 0-1 dkH, but also keep Ca:Mg ratio around 4:1 and trying to keep water hardness very stable (approx 4mg Mg and 15mg Ca calculated) and rather low K - approx 4-6mg weekly coming only from carbonates. Once I've started to keep these parameters stable all the time, my problems with macrandra and A. reineckii have gone - and they reacted in very similar way to each other and similar to what I see on your 2nd image. Possibly (but only possibly, I think you'll need to test it) you may need more either Mg or Ca (depending how much you add by booster and how much is in the tap) - but I'm only guessing while thinking about my experiments with water hardness in the past. I don't use gaseous CO2 at all by the way.

 

[Plants101]

Hey @Plants101 I think question is what is in that 1dGH and in your tap - how much Ca, Mg etc in relation to each other. What I can see in my tank is that R. macrandra without any doubts prefers softer water - I keep appr 3-4 dGh and 0-1 dkH, but also keep Ca:Mg ratio around 4:1 and trying to keep water hardness very stable (approx 4mg Mg and 15mg Ca calculated) and rather low K - approx 4-6mg weekly coming only from carbonates. Once I've started to keep these parameters stable all the time, my problems with macrandra and A. reineckii have gone - and they reacted in very similar way to each other and similar to what I see on your 2nd image. Possibly (but only possibly, I think you'll need to test it) you may need more either Mg or Ca (depending how much you add by booster and how much is in the tap) - but I'm only guessing while thinking about my experiments with water hardness in the past. I don't use gaseous CO2 at all by the way.

That's an interesting idea. I don't know the ppm of Mg and Ca in my tap, i'll have to look it up. I have alternanthera reineckii in the same tank and it is doing fabulous. Leaves are completely flat, not a speck of algae, and no stunting. Just macrandra thats giving me issues.

My other tanks with macrandra have the same tap water and they seem to be fine. Maybe it's a stability thing though, like you've said earlier, because I don't do water changes on those two other tanks. I just top them off when they get low.

 

[Plants101]

Okay so here's a weird update. I realized that my macrandra in this tank specifically has always looked like this, but actually appears to be healthy and nearly flawless at the end of the photoperiod.

It's this new quarantine lifestyle that led me to observe this. Previously, the lights would turn on while I was away and I would return for the last hour or two of the photoperiod to observe these perfect, sparkling macrandras.

But now, I'm here all the time and I mainly work on my tanks in the morning when the light turns on initially. When the light turns on, the macrandras look terrible. The leaves are twisted and ugly when the plant "wakes up" as shown in the picture above. But toward the end of the photoperiod, the macrandras look amazing.

This is weird because in my other tanks, the macrandras look great from start to finish of the photoperiod. Not sure why this is happening.

 

[Plants101]

Update: I thought I had found the solution, but I didn't.