Journal MarekM`s 450L - struggle for healthy plants

[marekm]

I have been running planted tanks for 3 years now, I started with a 200L one, which I have recently upgraded to 450L, there are algae and plant health issues that I am trying to overcome, any help more than welcome!

age: 3 months
Size: 150cm/50cm/60cm, 450Litres
Substrate: old ADA aquasoil (3 years) + a fresh layer of aquasoil from a local brand - should be fairly lean in terms of nutrients, especially ammonia.

Filtration & circulation:

• Oase Biomaster 600 canister filter (1200 lph)
• Aquael Ultramax 2000 canister filter (2000 lph)
• Aquael Circulator 500 powerhead (500 lph)

The oase filter is connected to lily pipes, and the aquael one is connected to spray bars running across almost the entire tank length.
The intended flow is shown on this picture:


Lights: Chihiros WRGBII 120 running at 60r/37g/46b, running for 8 hours straight. Using Photone app with Iphone 12 I should have around 50 par on substrate level.

Crew: 5 pearl gouramis, 10 lemon tetras, 20 rosy tetras, 30 neon tetras and a couple others

CO2: Distributed via inline difuser (quanvee) from Oase Biomaster 600. Dialed in via PH profile - typically 6.9 in the morning before CO2 injection, targeting 5.8 during light period with a max. of 0.1 ph shift during light period. For this I am starting the CO2 injection 5 hours before the photoperiod.

Water changes: 50% each week, the water is prepared in barrels 2 days before the water change and enriched with 10 ppm Mg, 4ppm NO3, 1ppm4 PO4, 2ppm K. The main reason for using barrels is that I want the water to let chlorine evaporate and the temperature to rise.
I am not using RO, since my tap water is 2dKh and 5dGh, so until now I did not see a reason to complicate things with RO.

Fertilization:
Micros: I have recently stopped using YaraTera tenso cocktail, which probably was causing micronutrient toxicity in the tank - more details here. For now I am using Seachem Flourish twice per week + Seachem Flourish Iron 3x per week (0.1ppm Fe x3 = 0.3ppm Fe per week from Flourish Iron + around 0.1ppm from Flourish).

Macros:
Weekly dosing 11ppm NO3/ 3ppm PO4/ 7ppm K split into 3 doses per week, plus an additional dose(4ppm NO3, 1ppm4 PO4, ppm K) added after water change.

For nitrogen I use a blend of KNO3, MgNO3, CaNO3 and Urea in ratio of (4:3:2:2) - the ratio is for the NO3 content. The reason for using MgNo3 and CaNO3 is that in the past I have measured very high amounts of potassium (50+ ppm) using the JBL potassium test kit, and some sources on UKAPS claimed potential potassium toxicity at those levels, so I have limited dosing K using this ratio. In the current tank the test kit suggests levels around 10-15 ppm of K.
For phosphates i use KH2PO4 and for potassium nothing additional, the 7ppm is contained in the nitrogen and phosphate doses.

Chemistry:
As said I have KH of around 2, GH of around 5 and nothing in the tank (seiru stones, ...) that should affect these.

 

[marekm]

Now for some plant photos I took today, around 7 days after I have stopped dosing yara micro and a 70% water change:


Rotala Russila orange juice
This is the most stable plant in aquarium, it grows in fast rate and maintains decent health (at least for the top half). It started showing some yellowing in last few days.


Rotala Wallichii
this one just refuses to grow, I am hoping it will improve as a result of reduced micronutrients


Rotala Bonsai in the center (and monte carlo on the right side)
This one also refuses to grow, bought as invitro almost 2 months ago, the growth has been minimal.


Bacopa caroliniana
The new growth looks ok-ish, but its a slow/medium grower, and the bottom half eventually deteriorates and algae attacks it.


Ludwigia repens mini Super red
Same as bacopa, new growth looks good(to my eyes at least), but the bottom gets attacked by algae.


Hygrophila guyanensis / nervata
This one is doing worse and worse, I would say the leaves are showing some nutrient deficiency for sure, but I dont know which one.


Echinodorus
The new leaves often look yellow-ish, then they shift more green and after some time they deteriorate and algae attacks them.

If anybody can identify something obvious that I might be doing wrong, please let me know. I am trying to be patient and introduce changes slowly, at the moment there is only 1 week after limiting the micro nutrients, so I still want to wait at least another 1-2 weeks before changing another thing.

The list that comes to my mind to try next:

1. get rid of purigen from filters - I have read here that some people observed improvement in plant health after removing purigen
2. bump up potassium - even if the test kit shows there is plenty of potassium(10-15ppm), the hygrophila looks like it lacks potassium I guess
3. reduce light levels - I was trying to increase light levels hoping that rotala wallichii needs it for growth with no luck, so I think I could reduce it by 10-15%

 

[marekm]

2 more notes:

• one of the reasons I am limiting potassium is this article, it mentions a Ca:Mg:K ratio of 2:1:0.5 to be ideal
• sorry for the crappy photos, I have a decent phone but for some reason I am unable to take good photos with it

 

[marekm]

View attachment IMG_9264.mov

 

[marekm]

View attachment IMG_9264.mov

 

[Unexpected]

Looking good so far. If I’m understanding right, you used some old substrate (about 3 years old) along with some new soil, but realistically both have only been maturing for around 3 months. I wouldn’t stress about it at all. From my experience, this is just that in-between phase where the tank is still settling in and doing its thing. It just needs a little more time.