Odd Shaped 40g heating

[Ginger]

Ok, so after having a good think about it, I have come to the decision of either purchasing a UTH, sticking to the side of my tank and insulating it, OR purchasing a CHE and switching it with my moon-glo bulb (appps, yes it is a ceramic fixture) and, my apologies I relised that my bulb is:

50 watts NOT 10 watts

After having a discussion with a lady at the petstore who owned bearded dragons and used 100-150 watt CHEs which heated her large tank (larger than mine) to 40 degrees (celcius), I THINK that a 50 watt would effectively heat my tank to around 27-30 degrees... The picture below shows the size of the 50 watt fixture compared to my mesh lid, it seems very small, but I have not had any experience with CHEs... Any thoughts regarding whether this would effectively heat my tank would be much appreciated.

[appps]

Does something normally fit over the mesh to keep the heat and humidity in?

If so I think the 50 should work.

[Ginger]

Yes appps, I do have a covering. I just took it off for the photo. This is what it usually looks like:

[appps]

Should be okay then. If you find it's struggling I'd look at getting a cover that fits all the way across though, stop that heat that's going to escape out the sides. You may find you need it to keep your humidity up too as the CHE dry the air out more.

[Ginger]

Ok appps, I will take that into consideration. May I ask:
1. Why does a CHE dry out the air more?
2. If I were to use a UTH, what wattage would be needed?
3. How do you insuate a UTH on the side of a tank without creating a fire hazard?

[appps]

Don't know to be honest. Guess it's a bit like a puddle on a sunny day compared to an overcast one. The hotter day will cause the water to evaporate quicker and the CHE will cause the moisture in the air to evaporate quicker because it's hotter. It's just something I've read and not thought too much about lol
I have a waterfall and a large salt water pond in my tank so large amount of water and yet my humidity still only sits at 85%. If I only had water dishes I think I would be misting or wetting the substrate a lot to keep the humidity up.

Some brands of uth say you can add polystyrene to the other side of them to help insulate the tank and direct the heat in. I think I would only do that though if listed on their instructions.

I have no idea on wattage for the uth. I do know it took two, a large and small, to keep my little tank warm on cool nights but I think it would have struggled badly in winter so think I'd go more rather than less. It can always turn off if too hot. But if it's not hot enough you have a problem.

[Ginger]

Thanks very much for all the advice, I will have a bit more of a think about. I apologise for not replying earlier, however I am quite busy at the moment.

[Ginger]

Sorry to continue on with this post, but I thought it would be OK to give a bit of an update and some questions on my heating.

So I now have my 20 watt heat mat insulated with Alfoil, Cardboard and Styrofoam on the side of my tank, and it covers a reasonable amount of the side of the tank *ABOVE SUBSTRATE LEVEL*. At that side of the tank it heats up to an average of 24-25C (75-76F) during the day (it is Winter here in Australia at the moment) with the cooler side being around 20-22C (71-72F).

However, I have found that since giving this heat, the crabs all sit right up against the glass at any level during the day and will not move. At night they will come out to eat, drink, explore etc. before returning to the same spot. I understand that Winter is a less-active time for the crabs generally, and they are obviously enjoying the warmth, but my question is... Do I need more heating? The tank will get up to 30C (86F) on the hot days during Summer without heating, so if possible I would like to avoid having to buy extra just for winter.

[emmac350]

Do you have any sort of light for them to bask in? My crabs spend a lot of time during every season basking in my night lighting. I have a low-watt moonlight bulb that's on all year round and a CHE that's on a thermostat as needed. At least one crab will bask in the moon bulb or CHE every other day.

[appps]

Hmmm just thinking outside the box, but it wouldn't be that that area seems more protected to them because all the sides are covered that's attracting them do you think?