If there is no light then you can never grow algea. Most tanks really are dark inside and so this is not the issue. Algea is a plant that requires sun light.
The issue is what water you choose to put in the tank. Pre filtering water before you add it to the tanks goes farther than anything else. You can rig up a set of two stage whole house filters that you can connect up to your hose to fill your tanks with filtered water. In a dark tank water can stagnate for a long period of time and still be safe. In a tank that gets sun light it won't last more than a week or so and you can never keep it clean.
Publicly treated water is about as chlorinated as required adding more won't really improve the safety of the water. Adding other chemicals probably won't help either. Perfoming a shock treatment on the tank does not require a very high level of Chlorine and should not be needed regualrly. Using a higher does really won't do much more. You need to be kind to your plastic plumbing and high concetrations of chlorine won't help. Don't play chemistry set with your drinking water.
If the water needs Iodine I'm not putting it in my tank.
Adding a tap filter is not a bad way towards making your water taste a bit better either. Put the most attention to what you put inside the tank in the first place. You can't make a cocktail that will clean contaminated water once it is inside the tank.
Last edited by PaulBl; 10-09-2006 at 08:37 PM.