Wobster is right, when cloning it really is best to allow at least 2 weeks for a good rooting system to build up and dont pull out the cutting/s to see if there are any roots. All good things come to those who wait
ive taken thousands cuttings over the years and have only lost a few in my time. I 'always' use a 2ft Aquarglo fluresant light for cloning which is about 18 watts (18 hours on and 6 hours off) with room temp between (76 - 80). i keep my clones about 7 - 10 cm from the light at all times and spray once in the morning and once at night with tepid (pre-boiled & airated) water. I always use rockwall pellets and i do confess i also use clonex though you really dont have to use a roting compound at all it just mearly speeds rooting by a few days or so.

Don't add any nutes to the water at all when cloning, they wont need it until there is a rooting system developed.

Some good things to remember when cloning:::

Best light cycle is either 24/24 or 18/6
Best room temp 75-80
Best sizt of cutting 3 - 4 inches from a new soft stem
Spray leaves with tepid well airated water twice daily(with lights off)
ALWAYS use steralized utensils when cutting
NEVER put rootless clones in direct sunlight they WILL die
What you choose to root your clone in is optional
Don't keep handling the clones let them do their job(caution is needed when handling clones because if you have been handling other plants you could potentially transmit deseases from other plants to the clones)
A dome is not a vital need though it helps keep the moisture in for longer periods.
Most important requirement is Patience

just my 5 cents worth