Lessons Learned During A Deep Clean 6

[JediMasterThrash]

Please see my other post for pics and description of my new crabarium iteration. This post details lessons learned from my previous iteration.First lesson, the most important, is about water quality. I’ve struggled with this a bit from the start. My first iteration, I had somewhat smaller pools, and I would fully clean them every week. That was my most successful crabarium, with only two deaths over 8 months. And this was despite the enormous amount of mold that grew on the wicker baskets that were half-buried under the moist sand. The next iteration I got the waterfall, which was impossible to clean. And then got a large pool with a table fountain in it, plus the waterfall. I thought that the constant circulation from the waterfalls would keep the water healthy, but I was quite wrong. I had a lot of deaths, especially the new delicate strawberries. So I got the 3-stage filters. The filters definitely kept the water cleaner. Even when dirty, it still smelled nice (as opposed to without the filters were dirty water smelt like rotten sewer). But the filters still aren’t enough. After about 3-4 months, crabs would start dying. It had to be the water. I think that you simply cannot cycle only 1/2 gallon of water. I think I read before during research that you need at least 5 gallons in order to maintain a cycled water system. So the upshot is, even with filters and clean water, you need to regularly completely clean the large pools. Especially since, even with the filters, the crabs simply poo faster than it can be filters. It’s amazing how much poo they can fling into the pools. And if you have coco-fiber substrate, whoo-wee!In my last iteration, I didn’t have deaths for the first 4 months, and then suddenly started getting a couple a week. Then I started fully-cleaning out both pools (FYI, I always cleaned the filters once a week and replaced the carbon once a month) once a month, and after I started that, no more deaths.The problem was that it was hard to clean out the pools. They’re in the back of the large tank, and half-buried in sand, and large and filled with water. Usually I wait until the water is low, empty what I can, them pull it all out, trying to be careful not to cave-in the sand-walls around the pools, and worried about disturbing crabs buried under the pools, and also having to re-level the pools, and hoping I don’t crush crabs when I put the pools back (the crabs digging would cause the pools to start leaning on the side or corner).So, this time, as I explain in my other post, I put mugs under the pools to act as pillars. So now there’s a safe surface to place the pools on, without worrying about the crabs underneath. The pools are also up much higher now, since, as explained in my other post, I added mesh sides for climbing in and out. So there’s much less sand-wall on the sides. There’s a good 4+inches of depth under the pools now.Second lesson, is about providing enough shelter on the surface. I went into detail in my other post, but my tanks had been getting rather sparse on the surface, and I’d been seeing much less of my crabs. They’d stay buried, or hiding in the bonsai. Usually just a few regulars who always enjoyed climbing on the waterfall and waited every night to be first in line for food would always be out. I figured that the problem is not enough shelter on the surface. They had to hide underground or behind the few shelters they had, and didn’t feel secure enough to be out and around the tank more often. So this time I added much more shelters on the surface. I put the two Chinese temples on the surface, plus a fake hollow-log, plus a real half-log, plus a hollow cork log, plus the bonsai, all on the surface. I’ve decided that jumbos and larger crabs are fully capable of climbing under or over things, so I shouldn’t worry as much about making sure there’s enough girth for them everywhere. And crabs prefer to bury by digging under something anyway, so I don’t need open sand for that. I also added real moss beds for them to bury into, and I doubled the amount of fake-plants in the crabitat so they have more security even when they’re out climbing around. I also put a wicker thing on the second level that has many hiding places in it.The moss is also for the thought that strawberries or other crabs that have trouble molting might have an easier time being able to bury into a softer surface substrate than deep down into the sand.Third lesson: I think crabitats need more daily variation in temp and humidity. In their natural habitat, the temperature will range 30 degrees from day to night, and relative humidity 25%. I think it’s completely unnatural to give them 24/7 of 78o and 75%. So this time, I placed both one of my night-glo fixtures (2x25w) along with the 15w repti-glo 5.0 fixture on the same day/night timer. So they’ll get 115w during the day and only 50w at night. The difference in radiation will chance humidity as well as it changes how fast it evaporates water from the pools, and of course relative humidity changes as a function of temperature too.Forth lesson: No mold! There wasn't any mold anywhere at all in the tank, and I had cholla in direct contact with moist substrate for 7 months. It has to be some combination of the heat/lights, and the fresh airflow from the tropicair humidifiers. I think having higher temperatures and lights is really a main factor in keeping the mold from growing.

[NewCrabber]

Thanks for sharing that, JMT, I always look forward to reading your posts. So what is the high and low temp/humidity in your tank? I'm a little concerned, more so for newbies who read the range you mention. They may be left with the impression that if they start out at 70° it would be okay to allow it to drop to 40° over night. Too, I think we have to keep in mind that they are in crabitats and not in nature. Of course, duplicating as much as we can is a good idea and probably the best environment for them, but I think it's also prudent to remind everyone that what works in one crabitate of a particular size may not work as easily or affectively in another.

[JediMasterThrash]

I actually can't give exact numbers right now, because crabs ripped my temp gauge off half a year ago and dumped it into the water pool, and that destroyed it. I was using a keychain thermometer laid in the wicker basket, but it started rusting from the high humidity, so I took that out. And my hygrometer seems to have died. I noticed that after having the tank empty and open to the room for a day, the humidity never dropped below 69%. Even in the fridge it barely dropped below 60%. That can't be right, it should be around 60% in the house, and 40% in the fridge.So I bought new ones, Kritterz (with a Z) again, but the temp one was busted when I opened the package - the plastic faceplate came out. And the humidity one was also busted, as it was reading 70% in the house. So I have to take them back. I gotta find some Flukers again. Those were far more reliable. Even in the store when I bought those, I checked all 7 packages against each other, and they varied by over 8 degrees and 10% among the lot. I picked the package that had the median values.They have the digital ones, but I remember reading that those were innaccurate? Also, how well do they hold up with the humid, salty air?Luckily I know my crabitat's stability quite well now after 3 years, so I know how it's doing without gauges for the time being.I estimate that my temperature variation is between 74 and 82 degrees night and day, and humidity around 74-82% as well. And there's also level gradients. Near the surface, it's probably more humid (85%) but cooler, and on the second level, less humid (74%) but hotter near the lights (85).I recommend probably 10% and 10degrees variation as starting points for testing this new method out. I also still don't recommend dropping the temp below 68 or humidity below 65 for any circumstance, and think that 72-85 should be the target range for both. So a new crabber that has 70 degrees, this is your *night* level, and you need to *increase* it by 10 degrees for your day level. Don't decrease it.

[JediMasterThrash]

Also, I'm pretty sure that you're asking for crab deaths if you let your temp drop below 60 for a couple of nights.Fifth lesson: I bought some new crabs several months ago, and put them in ISO. The ISO was next to a vent, but I closed the vent. The crabs were from very good pet store conditions, so I was suprised that I suddenly lost 4 to PPS.A few days later I discovered that at night, when the air came on, the vent, which I thought was closed, would fling open by the air pressure, and the temperature in the ISO went down to 55o. Ack! I then covered the vent with a blanket and laid books on it to fully block the air, and that worked, as i didn't have any more deaths and the temp stayed where it should.

[NewCrabber]

Thanks for that info, I'm sure it will be useful, especially for the newbie. I'm really not qualified to give advice regarding digital gauges. I first started out with Fluker analog. Eventually they became corroded and I then tried a Kritterz someone gave me. After that failed to register accurately not long after I began using it, I purchased a somewhat inexpensive digital, two in one from Walmart. That lasted less then a month before it no longer registered humidity. I went back to the Fluker analog. I'll soon be on my third set since my hermies made a tire swing out of the last ones , but so far, they've been the most accurate for me. I have read here though, that the right digital is more accurate and lasts longer. I think the brand most often mentioned is Tomy (Petdiscounters carries them, I believe). The idea that the loss of four hermies that came from decent pet store conditions had to do with the open air vent sounds reasonable enough to me, but I have to tell you, I'm still perplexed by some deaths, even after nearly five years of crabbing. There are certain things to consider such as water quality as you mentioned, healthy foods, conditions, etc. And yet when all seems in order, how do we explain deaths that happen for no apparent reason? Several weeks ago I picked up eight hermies, these were true rescues. They were more or less abandoned and left out of doors. I live in a warm climate and at the time the weather was in the mid 80's, high enough humidity for sure, rained a lot, plenty of leaf liter and insects to eat, etc. I set up a tat for them and decided to use a screen lid and put it in an enclosed lanai. No air, windows open, conditions a little above average during the day and within range at night. I thought it would be advantages for them, but it didn't turn out that way. I lost the first two days later and three more during the following two and half, three weeks. The remaining four are doing okay, but I'm still on the edge of my seat waiting to see how they will fair in the long run. I just don't get it and would have no idea what to tell someone in my shoes. I'm truly at a loss coming up with a theory on this one. Any thoughts?