New Tank

You need the aqua plus water conditioner as that removes chlorine from the water.

But the Cycle product is one of those that is known to have llittle effect. Use it if you want but don't expect it to do anything.

When you set up a new tank, you need to grow two species of bacteria in the filter. The first one uses the ammonia excreted by the fish as food, and it turns it into nitrite. The second uses this nitrite as food and turns it into nitrate. Both ammonia and nitrite in the water are posionous to the fish; nitrate is only poisonous at high levels. The problem is that these two bacteria take ages to grow, typically several weeks. And the nitrite eaters can't even start until there enough ammonia eaters to make nitrite. The process of growing these bacteria is called cycling, a word derived from the nitrogen cycle, the process I have just talked about.

Nutrafin Cycle is one of those products that claims to add the filter bacteria. The vast majority of this type of bottled bacteria don't work, leaving you doing what is called a fish-in cycle.

There are basically two ways to cycle a tank, with fish and without.
Fish-in involves a lot of water changes, at least once a day at the beginning. The level of ammonia and then nitrite must be kept low by these water changes so that the fish don't get poisoned. It does make the growth of the bacteria slower, but at least the fish don't get sick or die.
Fishless involves adding ammonia to the tank before any fish are put in, and this feeds the growing bacteria so that once they have grown in sufficient numbers it is safe to put fish in the tank.

I am giving you a couple of links which go into detail what is involved with both methods. Read them through a few times to get your head round them, then you'll be able to make a decision about which way to go.
fish-in cycling
fishless cycling

If you want to try a bottled bacteria product the one that works sometimes, but not every time, is Tetra Safe Start.

In modern tanks, the light tube usually fits into the lid with screw-on end caps at each end of the tube. If yours has these, it is safe. These end caps have a rubber seal inside to prevent water getting into the electrical connections, and in theory are supposed to be replaced every 12 months before the rubber seal perishes.




I say in theory because I always forget about mine