Thanks everyone
I put the playsand in yesterday, and it is really obvious to me even that they prefer it, there has been a lot more activity since then. I did run a fairly large magnet through it, and it didn't pick up anything? Jo, I would much prefer coco fibre I think, but so far I haven't been able to find it here. Or any better alternative. I still haven't got their proper tank (should be here tomorrow) so I am open to suggestions.
I also gave them some real food last night - fish, prawns, bananas and strawberries, and this morning there was sand all through the food dish, this never happened with the commercial stuff, so I can only assume they were happy with my offerings.
Now my most immediate worry is about the smallest crab. For a start, I am almost certain that he is way too big for his shell. At the moment I don't have any spares at all (except for one painted one which I am sure is too big for him anyway - it is no longer in the tank, btw). So I will be heading out today to see what I can find for him, but if I can't find any, my next option is to buy online which I imagine even once I have found some it will take a week or so to get them.
The other thing is that he has dug himself down under the sand over night. Perhaps not surprising, but frustrating that he couldn't wait until they had a proper home. Do they always stay down there for long periods or could it just be for a daytime nap? I am assuming once I set up the new tank that if he is still down there that I shouldn't disturb him? He has also dug right under their salt water bowl, and he is shallow enough that if I pick up the bowl to change the water that I will be exposing him - what do I do? The sand is deep enough that he could have gone deeper, but for whatever reason, he hasn't. I think the largest one is also trying to dig under too, and I haven't put enough sand in there for him to do it - I thought I had (I tried for just more than double the height of the largest crab), but it appears not. Should I top it up now (and in that case, is it ok to put extra sand on the one that is already under?), or wait until they are in their new tank?
Thanks Jo for the tip about the salt - the one I have is the 'hermit crab' type, so I will replace it. The one I have also doesn't have directions, so I have been guessing how much to use.
I don't have anything to add to Wai's thread for supplies yet as I haven't found anywhere that has had much to help me, but I am heading off now to check out a pet super store type place, so I shall report back. Fingers cross they have spare shells.
Oh, and I know painted shells are bad. But if that is all I can find until I can buy some online and I think the little guy REALLY needs a bigger shell (he can't even withdraw all the way into the one he has, his legs stick out), is it better to have painted shells available until I can get natural ones and hope he changes quickly? Or best to leave him in the too small shell for up to another week?