Bottom of Tank turning black

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NStalgia

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Can someone help me with my setup? The bottom of my grow out tank for my crayfish is turning black including the bottom of the rocks and the sand.
 

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As far as I can tell it started turning black from the bottom of the rock then the tank then the sand
 

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Looks like the beginning of black algae. Wash everything, including the sand. Rocks: rub with your hands or a small scrubbing brush. No soap. Sand: into a bucket and let water run, overflowing, turning and rubbing the sand every once in awhile with your hands to dislodge the algae so the water carries it away. Do this til all the black algae is gone. It may take 15-20 minutes depending on how stubborn it is.

Wash anything else in there, and also the container. Again, no soap, but lots of water plus friction with your hands.

There are several causes; the most likely, before freaking out and going the chemical route, are:

-Your water. Some tap water can cause this. Using purified water cuts down the opportunity for black algae to grow

-Too much food sitting around. Cut back on feeding

-Not enough cleaning. Regular water changes and the occasional vac, once you've done the thorough cleanse will do a lot to prevent the occurrence of it starting again
 
Must be our water. But it's heavily chlorinated so I keep a stock of water for a week and let the chlorine evaporate. I have 4 tubs like that for my juvy crays and this is the 2nd one I've found it on. The 1st one I've already soaked everything in bleach and moved my cray to a 2.5 gal. I'm wondering why it's happening all in the same week cause the 1st one was newly scaped compared to this one. I noticed it all as I was cleaning the substrate. Could it be the siphon I'm using that's why the other tanks are getting infected? I've seen people say it could be anaerobic bacteria from a lack of oxygen.
 
Also is it contagious? Cause I'm using the same tools for everything and I just finished setting up a Betta tank. If possible I don't wanna redo it again cause sticking those stems on a shallow substrate was a real pain. Haven't even added the rocks and other plants yet :(
 

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It is contagious and that siphon could be a prime culprit. As well as anything else you're using between tanks that include the ones with black algae or mold. I see something in the corner--a bubbler? Oxygen and moving water would be good, for sure. In the wild they don't have bubblers or filters, of course. But they have something they don't get with us--freedom to travel and change their surroundings, which includes bacteria that isn't healthy. We've taken that freedom away, so it's our responsibility to recreate the good environment.

Separate issue--it's a nice looking tank but what happens when crayfish climb up and out? It's not as attractive as what you have going on there, but a lid will keep them from going over the edge and ending up dead, either by landing on the floor or you stepping on one by accident.
 
Separate issue--it's a nice looking tank but what happens when crayfish climb up and out? It's not as attractive as what you have going on there, but a lid will keep them from going over the edge and ending up dead, either by landing on the floor or you stepping on one by accident.

And bettas are jumpers. I recently searched high and low after my new betta vanished during tank maintenance. After nearly giving up I found him in the heater compartment of the sump down the back of the tank.
 
No that's just my betta tank and I'm still looking for materials to make a lid for it and how to shape it. Originally I was planning to use it for shrimp and clown killifish but there's no way I'll be able to totally cover the top of it with plants sticking out of it which is necessary for killis. Will boiling my tools before every use be enough?
 
My very 1st one jump on my lap which freaked me out cause I thought it was some kind of worm (cause she was pink and I've had worms fall on me outdoors on different occasions which I still don't know where they came from). So I make sure everything has a lid even my shrimp tank and my crayfish tanks have weights on them cause they're fairly strong. This one had a plastic cover on the sides for now which I just removed cause I was cleaning it.
 
I'm not sure but it doesn't look like algae. The sand itself is turning black. This is the 1st 10inch round tub. I took out the bigger rocks 1st for bleaching and they look ok now just letting then dry in the sun for a couple of days before I reuse them. But this looks like the sand itself is turning black? The 3rd one is the 2nd tub that I was cleaning earlier with the bottom of the rocks turning black. Sorry I'm just getting really paranoid about what this could be. Looks like it always starts at the bottom.

Also my red female adult waiting for me to find her a mate.
 

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Cute crawfish!

Boiling isn't necessary, but there's a soaking technique with a tiny bit of hydrogen peroxide in a bucket of water to soak the things you remove. It's NOT adding peroxide to the tank, it's adding rocks etc to the bucket of water with peroxide, scrubbing, then rinsing thoroughly to be sure all peroxide is gone. I haven't done this so I don't have the technique. But it's readily available from numerous fishkeeping sites online.
 
Ok thanks. I'm gonna have to sterilize and clean everything then. It's gonna be a very long day :\
 
Ok so I tried bleaching the black spots and monitored them. Just in a min it started disappearing. The rocks I noticed took a day. So I bleached everything. 3 containers and the stones, driftwood even the sand. Gonna leave it for 24 hours and let it dry near sunlight for 3 to 5 days. Will that be enough? The 1st one that I treated is on day 3 now but the stones still smell like bleach so I'm leaving it to dry for a couple more days till the bleach evaporates. I think it might've contaminated my other tanks cause I'm noticing black spots on the bottom of my other juvi tubs. Gonna keep cleaning all the other stuff later or tomorrow after I find them a temporary container that's big enough for them.

For next time tho will dipping my tools, siphon, baster in boiling water before and after every use be enough to make sure my other tanks don't get contaminated again?
 
Right, if the bleach smell is there (I'm guessing you didn't go the hydrogen peroxide route, it has no smell) then washing again and scrubbing til the smell is gone would be a good idea. Leaving things in the sun is great for giving a boost to cleaning. I realize that in your locale some things like peroxide might not be readily available but sunshine is plentiful.

If there's no mold, algae, contagion, etc I don't see a reason to boil things. Then again, if that's what you feel is a working plan, go with your gut. The practices that keep this stuff away begin with having a filter, cleaning it regularly, and regular water changes.

As a test, I would try using bottled (not distilled) water for a few water changes, then slowly do a mix with the water you were using, then finally back to your local water and see if the problem returns. If it does, after doing everything else right, I'd say you've isolated the problem as being water-related.

Also, even though I suggested washing the sand, if you're really wanting to absolutely make sure you've done everything possible, consider starting over with fresh sand.
 
Yeah we don't usually keep peroxide. I'm not sure where the problem started but I checked one of my clarkiis old tub, cause I had to move her cause she's a bit grown now and everything was clean. No black stuff. I'm guessing it started in one of the newer ones and I remembered I found some mosquito larvae in one of my clarkii's tub and I used a baster to catch them and transfer them to my bettas and gouramis so I'm guessing they're all contaminated now too :\

I clean them every other night cause they don't have filters, only my fish and shrimp. And I do twice 100% water change once or sometimes twice a week depending if I can't get the water clear enough.

The sand looks fine but I'm not sure. Gonna monitor it for a week or just might change it entirely. Thinking of buying small lava rocks instead to make my specters pop more when you look at them.
 
Thanks btw. I don't mind redoing and rescaping everything. I just hope my plants weren't affected cause that might be impossible to clean.
 
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