Thanks for your comment on my tank. My DIY system works very well. I pay CO2 refill about $22 every 3-4 months. He (from fire extinguisher company) comes to my door or my work and refills the canister. As of today, all front plants are gone and I've just started Riccia project. I got stainless mesh and nylon net and planted small Riccia between them. Hopefully within a month or so, I should see golf course like green carpet on the front!!