Rotala indica struggling in tank looking for advice

[IntrepidUT99]

I have a 20 gallon long that has been up and running for a little over a year now. In July of this year I decided to do some rescaping in the back and removed the original background stem plants and replaced them with some rotala indica clippings. These clippings are from my other tanks where even if I tried to kill it, the rotala grows like a weed. However upon planting it in July, it honestly hasn't done much up to the present. Its branched out from the initial clippings I placed but it stalls as it attempts to grow upward. Just stops growing then algae slowly settles in. I clip the algae stems away, it regrows, stalls and repeats. I usually never use root tabs, but I gave in and tried those as well. That was 3 weeks ago, and I have yet to see much difference. At this point, I assume something is missing in this tank that the other tanks of mine have, but I am at a loss as all my tanks use the same substrate (inert sand and gravel) and water is the exact same parameters each water change between all tanks since I re-mineralize it myself.

I haven't noticed any other plant struggling in the tank, outside of the occasional old growth dying off of established plants. Other stem plants in the tank I trim monthly. I've also thrown an image up of the tank as well to this post. I suppose my questions are, what may be causing the rotala indica to struggle? If its not missing nutrients, is it due to another plant competing with it?

Background on tank:

Tank routine: 10% water change every 3-4 months with reverse osmosis water that has been re-mineralized with salty shrimp GH/KH+. Top offs are with reverse osmosis water only once a week or as needed.

Easy Green fertilizer is used once a week, and fish are fed every other day.  The lights are on 70% power and are on for 8 hours daily.

Water Parameters never really change in this tank, here are the results of testing prior to this post:

• Ammonia (NH3): 0ppm
• Nitrite (NO2):  0ppm
• Nitrate (NO3): 10-15ppm
• General Hardness (dGH): 9
• Carbonate Hardness (dKH): 4
• pH: ~7.4

Other plants in tank:

• Azolla (Floater)
• Red root floaters (Floater)
• Water Lettuce (Floater)
• Hornwort (Floater)
• 1x Amazon Sword (root plant)
• Dwarf sagittaria (root plant)
• Ludwigia sp. White (root plant)
• Ludwigia green (root plant)
• Susswassertang
• Various Buce clippings from other tanks
• Various Anubias clippings from other tanks

I think I've killed this post with data, if anything is missing let me know. 😅

 

Edited October 25, 2023 by IntrepidUT99

[nabokovfan87]

On 10/24/2023 at 7:41 PM, IntrepidUT99 said:

Tank routine: 10% water change every 3-4 months with reverse osmosis water that has been re-mineralized with salty shrimp GH/KH+. Top offs are with reverse osmosis water only once a week or as needed.

Easy Green fertilizer is used once a week, and fish are fed every other day.  The lights are on 70% power and are on for 8 hours daily.

Water Parameters never really change in this tank, here are the results of testing prior to this post:

• Ammonia (NH3): 0ppm
• Nitrite (NO2):  0ppm
• Nitrate (NO3): 10-15ppm
• General Hardness (dGH): 9
• Carbonate Hardness (dKH): 4
• pH: ~7.4

The one thing I would start with is upping the water changes.  You're not changing water nearly enough for a tank with that many plants and it might just be seriously struggling.  That being said, your testing looks perfectly fine.  There could be "something" that has built up in excess that is causing a bit of an issue and whatever nutrient the rotala is needing isn't quite there.  You can try something like adding iron, as a lot of the plants you have do use iron (ferns, suss, etc.).  Depending on what fertilizer you're using you could have some micronutrient that is missing as well.

@Seattle_Aquarist any ideas for this case in particular?
 

On 10/24/2023 at 7:41 PM, IntrepidUT99 said:

I usually never use root tabs, but I gave in and tried those as well. That was 3 weeks ago, and I have yet to see much difference. At this point, I assume something is missing in this tank that the other tanks of mine have, but I am at a loss as all my tanks use the same substrate (inert sand and gravel) and water is the exact same parameters each water change between all tanks since I re-mineralize it myself.

I would definitely use root tabs, but there are those that say the stems only get nutrients from the water column.  Out of curiosity, which tabs did you try out?

[IntrepidUT99]

Thanks for responding @nabokovfan87! Some more background per your questions/feedback. Due to being on well water (Liquid rock with a side of arsenic), I use completely reverse osmosis water for my tanks which then I use only two products to get the water up to par. Salty Shrimp GH/KH+ which is basically just a water soluble powder of calcium, magnesium and bicarbonates in a fixed ratio for the GH and KH. The other product is Aquarium Coop's Easy Green Fertilizer for plants. Both products have a listing of their contents, not sure if this helps narrow down if anything is building up in the tank. I also have non-API test strips to check for spikes in Iron, Lead, Phosphate, Copper, and Zinc. Granted test strip accuracy can vary, but the test strips come back in nominal ranges for Iron, Zinc and Phosphate and negative for the rest.

I am hesitant to dose increased iron into the water column as this tank does have black brush algae, I've won the long battle with it, but it loves to come out and wave at me through the tank if things go out of balance. Iron levels in particular. Is there Iron only root tabs that would work instead?

No issues temporarily going back to weekly water changes as an experiment with this tank, the head scratcher is some of my other tanks are currently on similar water change schedules of 3-4 months and the rotala in those tanks grows almost out the water a week or so after trimmings. If the water change works and nothing stands out in terms of build up, my uneducated opinion goes toward some sort of allelopathic conflict between the rotala and another plant in the tank. I am aware hornwort and dwarf sagittaria can do this to tanks if they are able to take over a majority of the tank, which is why I limit their growth. The one plant I am not too sure on is susswassertang. I have it in all my tanks, but this tank its by far the most successful in growth speed. I am not sure if any information exists on if the plant releases chemicals that can lead to allelopathy? 🤔

On the root tab front, I used Aquarium Coop's root tabs as a test. Usually for my planted tanks, I just use old substrate containing rich amounts of mulm/detritus from previous well established tanks I've rebuilt or torn down as a base layer in the new tanks that I cap with new substrate. It's my free aqua soil equivalent and why the amazon sword in the tank took over so quick 😅. To keep it going afterwards, I throw in pest snails such as trumpet snails.

[Seattle_Aquarist]

Hi @IntrepidUT99

Overall it is a nice looking tank I'm sorry to hear you are being 'challenged' by the Rotala.  All of the Rotala species are members of the Lythraceae which can be more challenging to grow.  Some of the Rotala species have a strong preference to substrate nutrients and suffer with water column fertilization.  There was an entire presentation done on this at the Aquatic Gardeners Association International Conference in 2019.  See Rotala Kill Tank

That said I see a two or three of symptoms which may indicate nutrient issues in your tank.  The first one is interveinal chlorosis on what appears to be a newer leaf of the Anubias on the left and the second is the overall chlorosis (yellowing) of the new leaf of the Anubias on the right.  Both of these symptoms are typical of insufficient available iron (Fe).  Iron is critical for the production of chlorophyll which gives plants their green color and produces the glucose that plants utilize for growth.


Now I know Easy Green has iron in it but unfortunately it is EDTA chelated iron which which is readily available when the pH is less than 6.5 but becomes less and less available to plants as the pH increases.  At a pH of 7.4 it is likely that less than 5% of the iron in the Easy Green is available to your plants. (see chart).

What I would recommend it continuing your nutrient dosing as you have been but augment the current dosing by adding Seachem Iron to your fertilizing regime.  Start by dosing the amount recommended on the bottle.  Seachem Iron contains ferrous gluconate which plants can utilize much more quickly and better in conditions where the pH is above neutral (pH@7.0).  Try dosing the Seachem Iron for one month.  The existing leaves will not change but hopefully what we will see is an improvement in the growth rate of all your plants including the Rotala.

If the increase of iron doesn't resolve the issue the last arrow on the bottom right shows 'puckering' of the leaf on the Anubias.  This may indicate insufficient available magnesium but since I don't see the condition elsewhere on your plants or on your new growth let's see how the increased iron does on resolving the issue.  Let us know how things progress!  Hope this helps!
 -Roy

[IntrepidUT99]

@Seattle_Aquarist thank you for the amazing response. I did sneak in a response above yours right before you posted. I do have black brush algae in this tank that does like to remind me from time to time it exists. I had a bad explosion ~7 months ago due to attempting an iron supplement in the water, it was Aquarium Coop's Iron product. I wasn't aware of the differences in Iron uptake at different pH levels that is good information. My question is, would using Seachem Iron risk another battle with BBA and would iron based root tabs be a better method? Or am I off-base?

[nabokovfan87]

On 10/25/2023 at 9:35 AM, IntrepidUT99 said:

I am hesitant to dose increased iron into the water column as this tank does have black brush algae, I've won the long battle with it, but it loves to come out and wave at me through the tank if things go out of balance. Iron levels in particular. Is there Iron only root tabs that would work instead?

I've got a link in my signature with my algae battle notes.  I've been fighting the BBA for years at this point and ultimately there's a few things you can do that help and some that don't really matter much.  In terms of iron, I started dosing it regularly again about ~6 months ago.  I started dosing it based on a post from Roy and realizing that I just wasn't giving the plants that nutrient specifically.  I have some plants that needed it and it's helped a bit.  It really helped out the moss I was growing. 

That being said, BBA is a bit of a pain and I understand the concern there.  Water changes remove the spores and that's where you might be running into those long term issues.

[Seattle_Aquarist]

On 10/25/2023 at 10:11 AM, IntrepidUT99 said:

@Seattle_Aquarist thank you for the amazing response. I did sneak in a response above yours right before you posted. I do have black brush algae in this tank that does like to remind me from time to time it exists. I had a bad explosion ~7 months ago due to attempting an iron supplement in the water, it was Aquarium Coop's Iron product. I wasn't aware of the differences in Iron uptake at different pH levels that is good information. My question is, would using Seachem Iron risk another battle with BBA and would iron based root tabs be a better method? Or am I off-base?

BBA seems to occur most in my tanks when I neglect my 50% weekly water changes and or don't clean my filters as conscientiously as I should.  I would be more inclined to suspect a build-up of organics rather that dosing of iron. (However dosing iron will make it nice and green and easier to see - lol) -Roy