Re-mixing old substrate?

[Kydra]

I actually sent a PM to @curlysister as I'm aware from her posts that she has had her crabs for years and don't believe any full substrate changes were done in this time from what I've read.

I currently have all crabs up and with issues of the top inch or so drying out, adding 20 ounces of freshwater from misting... I decided to remove everything from the tank and remix the substrate.

I did find some coconut shavings under a hut which I removed. I'm sure there had to be plenty of small pieces of food that I missed as well as all the crab poop since I typically just spot clean food here and there as I see it. My concern I guess is now that I've remixed the substrate, and with possible food pieces and crab waste mixed all in, should I be concerned about harmful bacteria growing or even possible bugs?

I do not use isopods or anything special for cleaning, but just thought with the consistency issues this was a good idea. Also thought I should just post this for others as well.

Thoughts on it being fine or would it be recommended to redo all of the substrate with new PS/EE before I have a crab decide to go down and molt? Thoughts? Thanks in advance!

[curlysister]

Sorry, I was off the forum for the weekend. With Christmas shopping and the wild stray cat in my garage (long story trying to catch the little creature), sorry it took me so long to answer!

You are correct that I have never thrown out all the sub and started again, and it was 9 years in September. Full confession - I also don't scoop out any poop. I just mix it in. I am sure that there has been bits of food etc that has accidentally been mixed in at times. If I see food, or bits of sub that have the white fuzzy growing that used to be food, I do remove that. I have always thought the poop would just kind of compost down into the sub. I'm sure there is bacteria, but it must all be good bacteria since I haven't had any issues. When both crabs are up, I will stir everything right to the bottom (or as close as I can get to the bottom). I might do that a couple of times a year.
Maybe it would be different in a different climate, but this has always worked for me.

[Kydra]

Sorry, I was off the forum for the weekend. With Christmas shopping and the wild stray cat in my garage (long story trying to catch the little creature), sorry it took me so long to answer!

You are correct that I have never thrown out all the sub and started again, and it was 9 years in September. Full confession - I also don't scoop out any poop. I just mix it in. I am sure that there has been bits of food etc that has accidentally been mixed in at times. If I see food, or bits of sub that have the white fuzzy growing that used to be food, I do remove that. I have always thought the poop would just kind of compost down into the sub. I'm sure there is bacteria, but it must all be good bacteria since I haven't had any issues. When both crabs are up, I will stir everything right to the bottom (or as close as I can get to the bottom). I might do that a couple of times a year.
Maybe it would be different in a different climate, but this has always worked for me.

Thanks so much. Appreciate getting back to me and totally get being busy!!! Good luck with the kitty cat lol.

Yeah, I've never taken out poop except changing water if there's any in there or cleaning shells. Just got me thinking. Since I did this, I now haven't seen my adopted crab for a few nights so think he was ready to molt. Hope it goes well as I had posted a pic a while ago and his exo was pretty beat up. And agree that you def got some good bacteria in there. Figured you'd be a good member to ask with your history.

Thanks again. Hope you enjoyed Thanksgiving and enjoy the rest of the holiday season!

[wodesorel]

The problem is the absolute mass of sand we use - it's never going to be fully bioactive because nothing penetrates that deep into a heavy thickness of substrate. Insects and beneficial bacterial need oxygen, and sand masses have a tendency to be anaerobic (lacking oxygen) just a few inches down. That's also what triggers the growth of bacterial blooms when coupled with wetter conditions.

If you've removed most of the biological material before mixing, then a few pieces here and there should not be a huge issue, but be cautious of the amount of moisture sitting at the bottom of the tank. I have had bacterial blooms get triggered by buried food and dead crabs in the past, but it has to be coupled with swampy conditions!

[Kydra]

The problem is the absolute mass of sand we use - it's never going to be fully bioactive because nothing penetrates that deep into a heavy thickness of substrate. Insects and beneficial bacterial need oxygen, and sand masses have a tendency to be anaerobic (lacking oxygen) just a few inches down. That's also what triggers the growth of bacterial blooms when coupled with wetter conditions.

If you've removed most of the biological material before mixing, then a few pieces here and there should not be a huge issue, but be cautious of the amount of moisture sitting at the bottom of the tank. I have had bacterial blooms get triggered by buried food and dead crabs in the past, but it has to be coupled with swampy conditions!

I had written a reply before work yesterday, but doesn't look like I hit submit before clocking in lol. Typical me .

Basically I had written a thank you for the caution and I will keep an eye on it closely. I did not remove any crab "waste" besides anything in the shells and water bowls. Did find a piece of coconut under a hut, but that's it. There is for sure crab poop and some itty bits of food now mixed in that I was unable to see.

I'll definitely err on the side of dryer sub as I've been trying to do since I've had them bacterial blooms. Of course it got a little too dry, but think I'm getting the consistency straightened out finally!

Just something I did then thought about it afterwards and was a one of those, uh oh what did I possibly just do kinda moments. I was hoping to not have to do a full substrate change until sometime in the spring at this point so will keep it monitored. I also want to upgrade AGAIN in the spring so we'll see how it goes.

Thanks again!