Humidity/temperature emergency in 55-gallon

Please post here if you are having a crab care emergency! Use a real subject and not just "HELP!"
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Location: Western NC

Humidity/temperature emergency in 55-gallon

Post by Picklesfoley » Sun Nov 17, 2019 2:45 pm

Since you've come to the emergency forum, we know you want a fast answer to your question. In order for us to figure out the problem as quickly as possible, we ask that you answer the following questions as best you can. Some of them may seem odd, but they're all designed to give us the information we need to give you a good solution for your problem. The things in the [ brackets ] are there to make this post easier to read once submitted. Thanks!

1. What kind of substrate is used in your tank and how deep is it?

Sand and EE, 5/1 mix.

2. Do you have gauges in the tank to measure temperature and humidity? If so, where are they located and what temperature and humidity do they usually read?

Temp varies, humidity too high (substrate was soaked).

3. Is a heat source used in the tank? If so, what?

Heat mats on back and one side.

4. What types of water are available (fresh or salt) and how is the water treated (what brands of dechlorinator or salt mix and what ratio is used to mix it)?

Fresh and salt, large pools in containers. Instant Ocean.

5. What kinds of food do you feed and how often is it replaced?

Fresh veggies/fruit, nuts, seeds.

6. How long have you had the crab and what species is it, if known?

6 crabs, longest 3 years, shortest 1 year.

7. Has your crab molted, and how long ago did it happen?


8. What type of housing are the crabs kept in, what size is it and what kind of lid is on the housing?

55 gallon tank, 2 plexiglass lids.

9. How many crabs are in the tank and about how large are they?

6, largest opening 1.5".

10. How many extra shells are usually kept in the tank, if any?


11. Have there been any fumes or chemicals near the crabitat recently?


12. How often do you clean the tank and how?

Water and food changes.

13. Are sponges used in the water dish? If so, how are they cleaned?


14. Has anything new been added to your crabitat recently?


15. Is there any other information you would like to share that might be helpful (anything that is regularly part of your crab care, playtime, bathing, etc.)?

16. Please describe the emergency situation in detail.

I have two large pools (together they're about the same as a 2 gallon tank), one salt and one fresh. Both have air stones and pumps. Recently I noticed mold growing in the substrate and today found about 1" of water in the bottom of the tank. Substrate was soaked through. I removed all the substrate and replaced with brand new play sand and EE. It's about 6-7" deep throughout. I used to have heat lamps over the tank but removed them due to hot spots, and the fact that the humidity was causing rusting on the bulbs and lamps. My house is about 72 degrees in summer and currently at 66 degrees (F). I don't know how to keep the humidity in, without it causing flooding, and without the temp being too low. Right now the tank is at 80F. I have two large holes in the top of each plexiglass panel where the lamps used to be, but have had them covered to keep the temps right. Should I remove the air stones and just change the water in the pools more frequently, while keeping the holes covered on top? Uncover the holes to allow the condensation created by the air stones to escape? If I take that path, how do I keep the temps up? Do I need heat mats on all 4 sides of the tank? I don't mind this but then I can't monitor the pools to make sure there is no water beneath it. I can provide a pic if you want (have to take one). This tank was never a problem with the heat lamps because it was so warm that the temps were fine and the heat burned off the majority of the humidity (although it kept it within a safe range). I don't know what to do because I know I can't change the tank monthly. I could use some guidance!! Thank you.


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Re: Humidity/temperature emergency in 55-gallon

Post by Meg'sAussieCrabitat » Fri Feb 14, 2020 7:13 pm

I'm not sure what you could do about the water pools. I've heard that some people use a splash guard to stop water spilling over, or you could just take the bubblers out. Another option that I use for constant humidity is a humidifier because it doesn't involve spraying and drenching the substrate, but if I keep it on low, the humidity stays around 85 all the time, but no condensation/flooding. Unless the temp is down you shouldn't need heat mats on all sides, because if it gets too hot your crabs have nowhere to escape to, which is why a temperature gradient is good. You can always experiment and see what works :)

3rd year of crabbing with my 3 Aussies; Lily, Cocoa, Mr Pistachio in a 65-gallon crabitat.
3 beautiful Sussex chickens; Adelaide, Geoff and Marshmallow

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Re: Humidity/temperature emergency in 55-gallon

Post by Maddamay32 » Fri Feb 14, 2020 11:14 pm

After a flood in my 30 gallon I upgraded to a 55 with bubblers in my pools which cause a fair amount of splash back. To combat that I bought a heat mad and attached it to the wall where I keep both water pools. The pool cover the side wall completely and so does the heat mat. I placed the mat so that it covers the outside all the way down to the base of my deep pools.
The sand is dry around them when I do water changes. I rely on the bubblers to keep my humidity at least to 80%. It's been almost a year and after checking for floods there has been no sign.

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9 crabs at the moment "Tarzan, Kermit, Shy guy, Eduardo, Jimbo, Sharkboy, Rosa, Diesel, Treaker"

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Re: Humidity/temperature emergency in 55-gallon

Post by Motörcrab » Sat Feb 15, 2020 3:47 pm

We had a very similar issues in two of our tanks with bubblers. Our 75 and 30 gallon tanks had flooding and bacterial blooms. Not a fun week at all. We ended up losing two crabs due to it.

I am not a big fan of bubblers because they can get out of control easily without constantly checking the substrate. Adding online air flow valves will help to control them to an extent. I like to put the air stones under the craft mesh at the bottom of the pools. It helps some with spreading the bubbles across the surface and helps make the bubbles in the water smaller.

The easiest thing to do with your pools is to add trays larger than your pools to catch a majority of the overspray rather than it going into the substrate. Maybe once a month you can remove the trays while doing water changes.

Adding dry moss around the pools can also help to collect the overspray too. You can rotate out dried moss from your moss pit with moist moss near the pools over and over.

With two UTH's that you can insulate should be enough to keep the temperature in the 80's. An 11x47 across the entire back and an 11x11 on one side should work pretty well. If the temperature get too high you can add a thermostat to bring the temperature down.

If you go with bigger UTH's you can cover the holes in your plexiglass lids. I use a plexiglass lid in the summer for a UVB bulb for my strawberries. In the winter I use a glass lid to help with humidity. Just a thought, depending on how humid your tank gets using just UTH's you can also turn on the lamps using the holes in the plexiglass here and there to "dry out" the tank too. When you turn the lamps off and cover you humidity will rise again.
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