Change out the CC like Scott did; over a 3 week period, replacing about a third at a time. You'll want to create a barrier between the sand and the gravel part to keep too much from getting mixed together. A small piece of plexiglass is great for that.
New dry sand will cloud the water for days. You could use the wet bagged sand from the lfs
that supposedly is LS
, or you could just buy play sand (kids sandbox) from a hardware store (Home Depot/Lowes, etc.). You can mix batches in a 5 gallon pail with a cup of your gravel and fresh sw
mix. Keep it heated and keep stirring it so that all the sand get's coated with bacteria. It should take about a week.
When placing the sand into the tank, first clear an area and section it off. Then you can fill some gallon plastic bags from the bucket, lower them in the tank and slowly release the contents. You could also use a section of large diameter pvc
(3" or 4") that reaches the tank bottom. Drop the sand into that and then slowly raise it.
Once sand has been coated by bacteria it will settle to the bottom within minutes of being disturbed.
The sand does NOT need to argonite. It can be any sand that has sugar sized granules. It should be a high quality sand like the sand that is fit for children to play in. All metals and toxic elements have been removed/screened out.
You want more ROCK. You should have 1˝ - 2 pounds of LR
for every gallon of tank capacity. You can get more base rock to save money. It will become LR
over the course a few months.
I would not lean any rock directly against the side glass. It should rest on the bottom glass though.