Yep - mine are all open too.

Do you think this might be a problem?

Thanks for that.
I'll give them a few to choose between.

Where did you get your shells from?
I assume they need boiling (or similar) prior to adding to tank.
I'm also assuming, since both mine are currently in almost identical shells, that the classic conical shape is preferred.

Interesting too that you know yours are "one red and one blue". All I've seen is the occasional leg.

I have recently purchased two hermit crabs. I know I need to offer them new homes in the form of empty shells. What I don't know is how many (I assume variety is good and more is better), how often they'll "move" and what type of shells they like.

Can anyone advise me?

Are there any clues that they are ready to move on?

Deano
It was me you gave the advice to and trust me I was grateful for it.
I don't want to use fish for cycling but I too have been told time and again by LFS that this is a good way to do it. My reason for not wanting to is based on having been "duped" by an LFS when I first set up a tropical years ago and watching the fish suffer.
The fact that you are on this forum and offering help shows everyone that you care about your fish, and theirs.

All the people on this forum are incredibly helpful and there will always be a mix of views on "the best way" and that's not a bad thing.
Anyway - thanks to everyone (including you Deano) for their help.

I had a load of red (I assumed it was algae) on my LR when I got it. Some of it appears to have gone white (I confess I didn't notice until just now when I read the posts above and went to admire mine).
Should I be concerned?
I have several snail-like creatures and a few millipedes (or worms with legs) as hitch-hikers if that is useful info.

Coralline, Swanny and Suitcaseyc (and others) I am much obliged for the info.
I have no intention of putting anything in the tank until I am confident the cycling has finished (or perhaps I should say started and finished).
I've been using tropical fish food as a source, perhaps I'll kick start it (again) with a cocktail shrimp to make doubly sure.

Thanks for all the help everyone.
I've just read an article in http://www.seahorse.org/library/articles/cycling.shtml
that suggests that if my LR was cured (and I confess I don't know ... yet) I might not see spikes in the tests.

Does this sound right?
If that's right, I might be looking at a cycled tank and not know.

Thanks Deano.
Much obliged for the help.

A bit more info (in case that helps anyone help me).
I don't want to add fish until the tank is cycled. In fact I want to get inverts in first then some fish (a couple only) later.
I am using RO water. Have not done a change but didn;t see the need as tests all coming back clean.
Should I be looking to introduce a crab or two, or perhaps a shrimp or two?

I have a "new" Orda TL-450. Bought it about 4 weeks ago. Let it all settle for a week then added live rock (as per LFS instructions). Found hitch-hikers on rock - delighted.
Since then I have been trying to get the damn thing to cycle. I don't know masses about this but am expecting the ammonia to spike.

Tests over a series of recent days as follows ...
Ammonia : 0____0.1____0.1____0.3____0.3
NO3 : ___10____5______5______5______5
NO2 : __0.1____0.1____0.1____0.1____0.1
PH : ___8.4____8.4____8.7____8.4____8.4
(Apologies for the formatting)
I suspect the 8.7 PH was a bad test (my fault no doubt).

On the advice of various very helpful people (thank you all) on this site I have been adding a small amount of tropical fish food to get the cycle started.

Nothing's happening (as far as I can tell) except a massive outbreak of brown algae. I have turned off main lights permanently (leaving only blue LED on) and this has seen off most (though far from all) of the algae.

CAn anyone offer advice on (a) anything I am doing wrong or (b) what I should be looking for.

I'm sure this must be covered all over this forum - apologies if I've missed it.

The rather lovely anenome (I think) that hitch-hiked has shrivelled up and may no longer be with us.

Absolutely.
All I have to do is figure out when it's finished ... or started.

Are invertebrates (and I'm thinking hermits and shrimps in case it matters) as delicate (or more so?)?