Stems Rotting Dead Center

I'm not sure how/why this is happening, but I know someone here will. I'd think I was doing everything right as I think I'm actually overdoing it. For some reason I'm having an on-going drama with my stems. I'm experiencing continued death two days after a huge water change and a heavy pruning of everything that was dying. Some stems don't even have leaves left, but I kept them because they have good looking offshoots that will probably be ready to trim come next Saturday. The glosso on the left isn't doing too much, but it's a fairly new addition so it probably needs time to root. There is some vertical growth.

Tank:
20 Gallon Tall. No Visible Algae.

Lighting:
2x24 T-5HO suspended 10 inches above tank and 24 total inches from substrate.

Substrate:
Onyx Sand/Worm Castings capped by Onyx Sand.

Flora:
7-10 L. arcuata
6 M. aquaticum
Newly Planted Glosso
2 H. Kompakt
2 C. Wendtii
1 H. Polysperma

Fauna:
1 Lonely Otto
2 Japonicas and 2 Pinnochio Shrimp deceased within the same 24 hour period, within 1 inch of each other.

CO2:
On one hour before lights with DC a very dark yellow when lights on. Seeing as all of my shrimp died I figured I'd go for broke. Diffused through needle wheel modified mini-jet 404.

Ferts: Liquid Dosing
12 mL Macro on Sun, Tues, Thurs (58.7g KNO3, 5.2g KH2PO4, 26.4g K2SO4 and 25 mL Excel in 900 mL solution)
12 mL Micro on Mon, Wed, Fri (82.1g MgSO4.7H2O, 13.8 CSM+B and 25 mL Excel in 900 mL solution)

Filtration:
Eheim Liberty 150. Yes Tug, I know it's underpowered . I have no livestock left other than 1 otto, so I didn't want to ditch the filter when all it does is mechanical.

Flow:
Liberty is turned full blast, mini-jet 404 that diffuses CO2 from left to right and 2 Maxi-Jet 404's (106 gph each) located on back glass and pointed diagonally towards the opposite corners of the tank on a wave timer. The 404's are located high enough on the glass to cause a bit of a ripple on the water's surface. I know the flow moves around well, as I have to replant stems 5-6 times a day and when I disturb the sand the powder goes flying around.

Unknown: GH/KH and no local tap water report.

Showing flow setup.


Leaves (or whatever they're called, fronds perhaps?) dying.


This one (short one on the right side of the picture) is rotting right in the center of the stem. It's now hunched over and probably going to break apart.


Just a cluster of death. Everything that looks yellow and brown is yellow and brown.

 

I had more. I started with 3 bunches of L. arcuata and 2 of M. aquaticum but they've slowly wilted away. That's why I have the bare stems in there with shoots growing off, I was hoping they'd save me the effort/money. I'll pick up more, though. The only algae I've seen in this tank was one tiny, barely visible spot on the top of the drop checker. Other than that, nothing. I'm not sure what my tap levels are for anything, Colorado Springs doesn't like to add too much information to their water reports.

 

I use Prime at every weekly water change. As said before I'll get more plants. Gah, I hate stems right now. I've had to shove a stem back into the substrate 17 times today. I don't even have 17 stems left in this tank. I've gone at angles, planted 2 inches deep and they still pop out. The powerhead is modified, and no CO2 that I know of escapes but I'll move the tube closer.
Time is what I'm afraid of, things have gone bad in no time at all..

 

You're right, I should have kept this to one thread, just came across different issues at different times and I wasn't sure they were connected. Sorry, as with the parameters listed on first post it's a 20 gallon tall with Onyx Sand/worm castings capped with onyx sand. I don't know GH/KH but I use GH buffer. (All of this additional info added to first post.) I have no livestock other than my otto. My two japonicas died last week, probably due to whatever is going on here. I bought two "pinnochio" shrimp and one was found dead on a powerhead but the other died by the next day. Actually the japonicas were found dead within an inch of the dead pinnochio, but they made it an extra day.
The only odd thing thus far is one day my tank smelled like a freshly paved road. Yeah, I know it's weird. I did two water changes in the next two days and things seemed to get better. Well, smell wise anyway.

 

Auto-fragging for propogation = self seperation of a plant to find better environment? New term for me.

If CO2:light is a concern then I don't understand what I once thought I did. A drop checker using fluid made from fresh baking soda (unopened box) and distilled water is highly yellow sitting 2 inches off of the substrate. I understand drop checkers are crude instruments, but it's at max capacity. I'm not arguing my case, just looking for an explanation as to how this isn't quite right. Actually, a few hours after those pictures were taken I was replanting and accidentally knocked the DC from the glass so it floated to the top. I pulled it out, allowed it time to turn blue again and placed it back in the tank on the opposite side of the tank. I checked it rougly two hours later and it was back to yellow.

My method behind the placement of the powerheads on the back glass, slightly higher than the CO2 powerhead, is to push CO2 down on the left side of the tank for 20 seconds, the right for 20 seconds, etc.

Lights being 10 inches above the tank is something I got from VaughnH/Hoppy's posts about PAR and height. I used this graph in conjunction with this thread. I figured 16 1/2ish" tall tank + 10 inches higher gave me roughly 40 PAR per bulb, times two bulbs is 80 PAR. From what I've read glass tops reduce around 6-8% of useable light, and 8% of 80 is 6.4 so I was still within medium-high lighting. It seemed like a fair trade off between loss of PAR I may not want and potentially refilling the tank daily as there's minimal humidity in Colorado and an open top seemed like a nightmare. All of this is just to show I put thought into what I was doing, even if it's misguided/wrong.

Back to the point at hand, if a CO2 increase is needed I'll do it. Just curious as to where I've strayed and I really don't want to gas my otto. My wife is already not happy with me for killing the shrimp.

My nutrients better be right, this is your recipe. Divided by 1000 (mL), then multiplied by 900 (mL).

 

Turning it up is a possibility, as is rethinking my entire setup. I just don't want to overdue it (read above in my response to Philosophos).

 

You're right about it being a lot of sand. My reason for that is I started with 2 1/4" in in the highest spots and it was relatively low in others, as I was trying too hard to "scape"(I use this term as it pertains to me extremely loosely). The sand/worm casting mixture ends right at the bottom rim of the tank, so in some spots there was more of that than just sand and I was afraid to pull up the worm castings. At my highest point now I'm at 3 1/2" but I feel better about my worm castings not coming up/out. I'll probably remove a bit of the sand in the future and use it to fill in spots of my 55 gallon that look rough. I liked the way my "scape" looked before, it was just too low and now it looks..flat. I read about onyx sand buffering your PH by 0.2-0.4 at the most, but I'm not sure about KH. I think my info came from APC's Seachem section.

As always Gerry says things I agree with, and CO2 is worth every penny. I just thought I spent enough.

My mini-jet is modded, but I like the design of what you've created and I'd be willing to try it out. The skimmer function would be a good addition. I have to pick up another glass top because the one on my 20 gallon is actually borrowed from my DSMing 55 so I'll see if I can pick up a Duetto at the same time.

 

No Excel in this tank, just in my stock solutions to keep mold at bay.

Quite a few of these stems floated in my tank for up to a week as I got fed up with replanting when I first set this tank up. There were subtle "curves" from them fighting around each other for light (my presumption), but not nearly to this degree.

 

To all, thank you for the continued help. I really appreciate it.

None of my responses are meant to be argumentative, just posed in curiousity and confusion as to what's going so horribly wrong.