Almost Done Troubleshooting, Still Stalled...

Hi everyone,



I've spent the end of the summer and early fall here troubleshooting my tank, which is still suffering from stalled growth despite my efforts to troubleshoot everything. My major issue is that somehow, everything was growing great 8 months ago. I had a crappy cheap light and was kinda just dumping ferts in randomly without much thought. This ultimately cost me some shrimp/fish/snails, so I backed way off and started properly maintaining my tank around July. Since late August my tank parameters have been pretty stable and using EI for weekly/no CO2, I think they are within range. Here's my parameters and fert schedule, followed by my troubleshooting and some pics



My current parameters:
64L (60x30x35cm)
pH: ~7.5
gH: 10
kH: 6
NH3: 0ppm
NO2: 0ppm
NO3: ~20ppm
PO4: ~3ppm (not sure on this and might drop over the course of the week)
Fe: ~0.2ppm (detectable at least)
Lighting: Chihiros RGB plus 8hr with 1hr sunrise/sunset at ~50% intensity on all RGB channels
Filter: Eheim 2213
Water Changes: 30-50% every Saturday morning 75%RO/25%Tap (Tap is very very hard and high in PO4, I THINK)

Fertilization: Macro/Micro alternating schedule
All values are per week, (dosed in usually 2 macro doses, with an off day or two before WC)
14ppm NO3 from KNO3
12ppm K from KCl, KNO3, KH2PO4
2ppm PO4 from KH2PO4 (just recently started this, see below)
5-10ppm MgSO4 at WC (still fine tuning this and not really sure if going above 5ppm is helping considering my hard water)
6mL AquaRebel Eisen MikroBasic
6mL EasyCarbo, irregularly dosed



I've been troubleshooting a few theories, so here's some possibilities and what I've done to mitigate them:

Flow: Eheim 2213 seems like its slowing down with age although there is circular flow over the substrate when observing small particulates floating in the tank. Had good growth with this setup before though…

Lighting: I added a Chihiros RGB plus a month ago and have it running about 50% power, which should be just slightly stronger than my old light. Creeping the RGB channels up 3% per week now.

Anaerobic substrate: Progressive loss of growth over the duration on the tank life. Bubbles observed from substrate when disturbed. Weak root formation and runner formation of formerly strong growers.


Ferts:

Micros: Was using weakly stabilized Micro and have now switched to a more appropriate stabilized MikroBasic Eisen fert. Fe levels are detectable across the week.

Phosphate: Haven't calibrated the kit so it's possible it is low. Unlikely though considering the kit results suggest 10+ppm out of the tap and tank levels around 4ppm. However, I do have green spot algae which many suggest is due to low PO4. I added a glass lid in february (less top off) and switched to higher RO ratio (less high PO4 tap water at WC) back in July, which possibly changed this more than I thought. Will add 1-2ppm KH2PO4 from now on just to see if it helps.

NO3 and K: Dosed regularly for more than a month now, adding ~15ppm Nitrate per week and 10-12ppm K (from KNO3 and KCl)

Magnesium: Currently adding ~5ppm with my water change. This definitely made a big change when I started dosing.


CO2: Tank growth is overall poor. Loss of DOCs from maturing substrate could mean less available carbon in my tank than in the beginning, is that right? I dose EasyCarbo to seemingly little long term benefit. Maybe I need better timing with this since I tend to add it only when I have time and am home.


Tl;dr: Tank stalled for 6 months. Troubleshooting most common things. I feel like it can't be my lighting because I had good growth with my crappy Nicrew and my new light is clearly brighter with better coverage. I also had nice growth with the same filter (2213) back in february. Same goes for CO2, I had good growth without it, why should I NEED it now? Micros should be better off now that I'm using the MikroBasic and have detectable Fe across the week. KNO3 and K should be fine with the amounts I'm dosing. I was suspicious of Mg but after a little improvement when I initially added it, it doesn't seem to help much (my tap water is also very hard). Is 5ppm good enough or should I dose 10ppm at WC? Most suspicious of PO4 because I added glass lid (meaning less top off) and higher RO%age (less PO4 added at WC) could've led to very low PO4. Adding 2ppm/week now, but just started this past week and seeing minor improvements. Definitely seeing an improvement when comparing my last 3 weeks of pics, but am I wasting my time and I just need CO2 to grow the plants I have?

 

Thanks for the reply.

I forgot to mention my substrate. It's a dirted tank capped with about 1 inch of black sand. I'm a little suspicious of it, because I used "Teicherde" which means pond soil. Supposedly it's high in clay and is designed NOT to give big algal blooms in your pond. Initially I was worried that it might be nutrient poor compared to normal soils, but I guess I kinda disregarded that once I got rolling. I saw a local German youtuber using this stuff with success, so I gave it a go. I'm in Germany, so I can't pick up the usual brands from the US and to make things more complicated, the German terms for topsoil and potting soil and so on are not super clear to me (not a native speaker). There's a pretty good German aquascaping forum called Flowgrow.de and I have to say that the general opinion of dirted tanks over here appears to be almost purely negative.

I added a decent amount of EasyLife Root Sticks when things started going downhill, to little/no effect (although to me these sticks look like pure clay sticks and maybe they don't have many macro nutrients. When this didnt work, I started suspecting anaerobic conditions in my substrate.

My rooted plants do seem to be doing poorly, but it somehow seems general as well. My java fern is in bad shape for instance. My subulata has just put out its first runners in at least 2 months.

How long does it take plants to recover from severe stunting? I'm only about 1 month in on my intensive care routine and I only started adding PO4 this week, so maybe I'll see some improvement stilll.

As far as calcium: Berlin tap water is super hard (https://www.bwb.de/de/assets/downloads/analysewerte-wasserwerke.pdf) with over 100ppm Ca. I figured using this in a 33%/66% Tap/RO mix should get me down to about 30-40ppm. Then I started adding the MgSO4 to try to hit the ratio.

 

Cool, thanks for the input again.

As far as troubleshooting my substrate, I've got a few ideas. The simplest is just going to be to pop in some root capsules and see if that helps. I don't have the biggest hopes for that since I already added easylife root sticks and got nothing. Also, since my tank got set up, plenty of sand has settled towards the front/middle of the tank due to the shape of my hardscape and flow in my tank. Over time I've added more to the back and more recently I started sucking out some in the front. It makes me wonder if the sand is just too thick, especially in the front of the tank. It looks like about an inch and change now, but I wonder with my very fine grained sand if this is too much and not enough flow is getting down into the substrate. I might just vacuum out a decent amount next time. To go along with this, I also have an observation I made back in Feb when the tank was still growing properly. It seemed like if I left the tank to sit and didn't do any water changes, growth would really explode after about 2-3 weeks. This happened repeatedly and was not dependent on my fertilization (at the time I began DUMPING ferts in the tank thinking I just wasn't at the correct concentration for good growth, to no avail). Now I realize there may indeed have been some other factor that was accumulating in the tank (DOC?? NH3??) that was helping the plants grow...

Anyway... I think it's weird that my L. cardinalis is just kinda stalling too. The L. repens I added with it seems to be doing pretty good in my back corner, but its almost like my cardinalis just used up his nice food supply he brought along and is now as stalled as anything else in my tank

And yes, I'm praying I'm on the road back as welll. Not totally convinced, but some of my plants are doing notably better. H. tripartita for instance just kinda sat there wilting for a long time but it is making a grab for my S. repens spot in the front of the tank. S. repens seems to have new growth coming in under the badly abused older leaves. S. subulata has new runners that are growing verrrrrryyy slowly but are nice and green and healthy looking. I just wish I could figure out H. zosterifolia!!!! I love this plant but it permanently looks like shit in my tank!