Comparing two or more things

You can fix the so-called problem by deleting "more" from the sentence. The strict rule is that when you say "more" you should also "than" what in the same sentence. A looser interpretation of the rules says that the comparision must be completed in the immediate context of the sentence -- the one or two sentences before or the one sentence after.

You can also change "more" to something that gives similar meaning but does not invite comparision -- added, extra,  and so on.

I hope this helps.