Love those shrimp and your tank! Did you dry start your carpet?
I'd be interested in your specs as well I also have a 5.5 I'm wanting to carpet.
I did not dry start. I just had wads of HC (yes, it's HC not HG) already from my 3gal pictope. It was growing really well there, and instead of trimming with scissors, I grabbed tweezers and pulled selective chunks of HC. I smoothed out the HC in my 3gal so there was no holes, and used the nice chunks to start carpeting the 5.5 tank. I put splotches of it apart from one another and used eco-complete on the bottom, black sand for the top so that the finer granules will give the HC a better chance to root.
I laid pyrex plates on top of the HC. The glass allows the light to go through. The HC was still pearling with the CO2. When the HC seemed better rooted, I took off the pyrex and the HC starting spreading out.
It's a paintball CO2 set up (1-2 bubbles per sec for 6 hours a day; goes off when the lights are not on). The lights are a homedepot $8 clasp lamp with a 6500k 24W compact flourescent light (supposed to be equivalent to 100W but that's not really the case when it comes to plants). I played with the height of the lamp when it seemed I was getting algae. I also have a second lamp with a 6500k 10W compact flourescent focused on corner where the other lamp cannot reach. Again, I play with the height so that I don't over light the tank and have algae problems.
I do regularly fertilize. Some think it hurts the shrimp. But so far, my shrimp have been doing OK. The CO2 is what I am careful about. I've killed a few by accident when the bubble count is too high.
The key with CO2 is water agitation and good circulation. If you look at the tank, I have sponge filters on both ends plus a regular Azoo 60 with shrimp prefilter guard. With plenty of water movement, and watching the bubble rate, I found a happy medium between having shrimp AND a nice planted tank.
Hope this helps!