About to get hermies. Advice?

[greengreen]

I have a 4ftx2ftx2ft tank set up. I don't have any hermit crabs yet, but when i do get them, they will be Coenobita variabilis, the species in the Australian pet industry. I have sand substrate, and a (marine) salt water pool at one end of the tank, separated by a perspex divider. I have small heat mats under the salt water end that I could possibly turn on to heat the water and aid in humidity, and a heat lamp attached to a thermostat. At the moment, it is 32oC in the sun, and 25oC in the shade, which is pretty similar to the weather of the parts of Australia they come from.
I have a hygrometer, but I have not calibrated it yet, so I don't know what the humidity is yet.
I have a large branch in the tank that gives a lot of area to climb on.
I have an assortment of shells, but I may need to get more, depending on the size of the crabs I get.
The tank is covered. (with some gaps for ventilation)
I have bowl for fresh water, and flat open sea shells for food dishes. I plan on offering a wide variety of fresh foods daily, in very tiny amounts, mostly vegetable matter, and some fish.

So, how am I going? I think all I have left is to make sure the humidity is good. Does anyone know what the required humidity range is for Coenobita Variabilis? If so, how do you know?

Also, I'm getting a light layer of algae on patches of wet sand. I'm thinking this will go away when the top layer of sand dries, but does anyone else have any thoughts or comments on algae? The sand on the 'dry' side of the divider (most of the tank) is actually damp at the moment; is that an issue for Coenobita Variabilis?

Also, does anyone know how big Coenobita Variabilis has to be before it is sexually mature?

I think I'm nearly there. How exciting!

[Wai]

I think the temperature is too hot. Yes, it can get that hot in the wild, but I would bump the temperature range down to 22'C to 28'C.

I'm not sure about the algae and whether it would mould on the sand, but algae is good for them to munch on.

Humidity should be from 75% to 85%, as for all other species.

Land hermit crabs do not breed in captivity.