Thanks for your input Frank. I bet it was quite a treat to pick Amano's brain.
I have to disagree about replacing 100% of the aquasoil before rescaping. Aquasoil is a great substrate, but I think with a healthy dosing of macro and micros ferts in the water column, the nutrients that may have been depleted in the aquasoil over time, can be replenished, or rather replaced through this method. Also, it has started to make complete sense to me why my hc in the initial months of this aquarium took off, then staggered. The aquasoil combined with the powersand, along with a heavy handed dose of co2 gave this tank a kickstart. But after 3 to 4 months, the HC depleted a good amount of nutrients in the soil after its rapid growth, and my dosing routine at that time was sub sub par. I wasn't adding adequate nutrients, and my plant growth stunted, and being still way too green behind the ears, thought the problem elsewhere. But really, it was my ignorance that got in the way. My knowledge of lighting and soils and co2 diffusion was rough to say the least, and only when I started to dig deeper into the hobby, trying to get a better grip of what goes on behind the scenes...the science...the tests that those have done on soils and light output and algae and macrophytes et al., did I begin to really unearth and dissect my "aquatic dilemmas."
I am going in the other direction in regards to the lighting. I strongly believe that light intensity is the driving force of energy into the aquarium. The 27w pc is a little too much muscle for me. I feel that reducing the intensity will have a positive effect. It will decrease the high demand of co2 and ferts and create a more placative and forgiving environment, especially for fauna.
As of today, I've removed all of the shrimp to another tank (low light and no co2). I tinkered a little with the scape, cleaned the filter, and added some more substrate to get a better sense of slope/depth. Bleached the pipes; cleaned the tubes; scrubbed the rocks. I am going to be doing a few more water changes than usual because of the additional soil and possible NH3 leaching. Getting the 18w bulb sometime this week. 18watts over 5.5 (more like < 5g with the rocks and dirt) tank sounds about right to me. I have to say, delving deeper and asking the magic question "why?" has given me a greater reach into the hobby. And I want to keep reaching for a better understanding on a factual level, rather than building on blind faith as I have done in the past.
all the best, walter