I am the installation manager of a fireplace company in Alabama. I have been in the fireplace industry for over 20 years. I also have gas logs in my own home. Properly operating gas logs should pose no threat to your reef tank or your family. That being said, I may know what the issue is that you were dealing with. It sounds as though the gas logs are new and ventless? If so, just about all brands of ventless gas logs require a burn in period of 3 to 4 hours during which they will produce some really bad odors. This is caused by a bonding agent on the logs which needs to burn off, etc.. It smells bad, but is harmless. I always advise our customers to pick a day when they can open some windows, doors, etc.. and go ahead and burn them off. If the fireplace is vented, you can open the damper during this time and close it when the burn in is complete. After this period, you should have no odors, if everything is operating correctly. There are many things, which can cause gas logs to produce excessive odors if something isn't set up correctly. These things can also cause many other problems in your home like sooting, condensation etc.. The best course of action would be to have someone from a local fireplace company check them out, determine which type of gas logs you have, clean them, and show you how to operate them correctly. I do this all the time here. You may even be able to add a wall switch or remote control to the set if you wish. The service charge shouldn't be to high, and you will have peace of mind, and much more knowlege about how to operate them after they are checked out. There are so many types of gas logs, and so many different types of controls for them, that there is really no other good way to know exactly what type you have. Best of luck!!