Water lettuce is going yellow

[Guppy10]

Hi all, iv got 3 types of floating plants but only the water lettuce seems to be struggling. They divide into smaller plants but don't seem to grow ! The Sprite and spangles seem to be fine tho not growing much if at all in a few weeks. I have a white led tube and blue and white above the water in the hood, light is not as intense as the fluorescents were but it's not a dim light. The plants get drawn to the infeed area from the external filter. Can anyone shed any light on why they don't thrive as iv no idea on plants,,, but read a lot about co2 and ferts but I don't want to go there or alter things as regards my fish needs as they are perfect. Any advise welcome.

 

[FallenPepper]

Use an iron supplement BUT like a dash.

 

[CryptFan]

They are yellowing because they need a fertilizer with iron, you could get a complete liquid fert or a liquid iron supplement.

 

[seangee]

You could try a liquid fertiliser like seachem flourish complete. Use half the recommended dosage.

FWIW I have never had success with water lettuce. They don't cope well with humidity on their leaves.

 

[Retired Viking]

I use Flourish for my plants, also at 1/2 dosage.

 

[Guppy10]

Thanks guys, seems I need ferts then. Iv just been and bought some elodea ( if I remember correctly ) , would the fert be beneficial for that too ? Will this not harm my water parameters ? Im trying for a more natural approach these days. Thanks all.

 

[Guppy10]

Oh, how often to dose tank with ferts ?

 

[Byron]

A couple of things here, which others have alluded to. First off, floating plants are fast growing plants because they have the aerial advantage; this means the leaves being at the surface can assimilate CO2 from the air rather than from the water, and air assimilation is about four times faster for plants. They also are closer to the light which is beneficial to fast growing plants. But with this comes the need for other nutrients to balance; it is unlikely you will have sufficient of these without using a liquid fertilizer.

Which brings me to the iron...don't. Plants require 17 nutrients, of which iron is one micro-nutrient. Chances are that without using any fertilizer now you are depriving the plants of several nutrients, one of which will be iron certainly. But "yellow leaves" is indicative of almost any nutrient deficiency and even light problems; leaves unable to photosynthesize will die and this means they turn yellow. A complete supplement is your best bet, and one like Seachem's Flourish Comprehensive Supplement for the Planted Aquarium or the near-identical Brightwell Aquatics FlorinMulti will be OK.

Adding iron when other nutrients are likely deficient willonly make things worse. I nearly killed off my floating plants in one tank by using iron (in addition to the FC) because it created an iron excess. Aquatic plants have a proportional requirement for nutrients, and the two products mentioned are designed accordingly.

Water Lettuce (Pistia stratiotes) does reasonably well in my tanks, though not in all of them equally. Which brings me to the next point, that not all plants will manage the same in every aquarium, and not all species of plants will tolerate each other in an aquarium. This is just for information; I've not the botanical knowledge to specify such an issue here, even if I did know all the other plants present.

Last comment on the light...red and blue are required to drive photosynthesis, and green in the mix does improve plant growth. LED is sometimes deficient in red, and red is the more important of the two (red and blue). Blue can cause algae issues if it is too high without the red in balance.

 

[Byron]

Thanks guys, seems I need ferts then. Iv just been and bought some elodea ( if I remember correctly ) , would the fert be beneficial for that too ? Will this not harm my water parameters ? Im trying for a more natural approach these days. Thanks all.

Oh, how often to dose tank with ferts ?

These posts came as I was typing the last one...all plants will benefit from liquid fertilizer. But you don't want to overdose it because it can encourage problem algae. The light intensity/spectrum must be in balance with the nutrients in order for plants to grow (photosynthesize). You also do not want to be overdosing minerals which may cause issues for the fish, but this should not be a problem unless you use more than needed.

As you have not been using any, try one of those I mentioned and use maybee half the recommended dose. Add it on the day following the water change.

 

[Colin_T]

Water Lettuce does not do well under covers. If you have coverglass or hood on the tank, they tend to rot. They need good air flow around them and bright light. Low light will hinder their growth and humid air or water splashing on their leaves will cause them to rot and die off.

 

[Guppy10]

I will open the cover flaps to allow more airflow n see what happens and try to get ferts on my next visit. Many Thanks.