[pogodzib]

Either the hermits are doing a good job at eating the algae or they could be starving. It is tough to tell, but my guess is that with only 6 in a 29 gallon tank they aren't starving.

Depending on how much LR you have and how deep of a sand bed, the nitrates may never come down on its own. In general, nitrates are only reduced in areas of the tank that are deprived of oxygen, such as deep inside of LR or in a DSB. There are other methods or corals that can be use to lower nitrates, but they usually aren't tried by someone that is beginning or by people that keep having the nitrates rise to much higher levels on them. What changes can help get it down, but from there, you'll need to wait and see if the nitrates hold steady, come down on their own, or start to rise again to know what you need to do.

Coraline algae will grow and spread on it's own with time, as long as some is introduced into your tank by scrapings or on LR. How fast it will multiply is dependent on your water parameters, amount in the tank to start with, lighting, and livestock. Some tanks take many months before coraline takes off and other tanks will have the whole tank covered within a month or two. FYI - Hermits get coraline so they can slow the coraline algae takeover down, but they also help prevent bad algae from showing up.