"Old Tank syndrome" and sandbed collapse

[ReeferMedic]

I just started in sw around eight months ago so I don't know all the ins and outs yet but I've been doing fw for over 20 years and those tanks can supposedly get "OTS" as well. I have never run into it in one of my tanks though. Maybe it's due to the way I clean the tank. Every now and then I do a cleaning of the sand bed. I use one of the clear plastic siphons you see in all the stores. What I do is put the siphon in the sand and suck up a column of it. Then before it can be pulled into the hose I stop the flow and let the column of sand collapse back down. I then restart the flow and pull all the nasty water and stuff that's been liberated from the sand out of the tank. This probably accomplishes the same thing as stirring but without allowing what you stirred up to circulate throughout the tank. Does this take out some of the bacteria in the sand bed, sure, but it doesn't wipe it out. That would be impossible. I also don't clean everywhere, just the sandy areas that are out in the open. So far this has worked for my fw tanks. Time will tell if it works with my sw tanks too.

You won't be able to do this with the fine sand that is in most of our tanks without losing most of it down the drain. It works much better with the gravel that is used in most fresh water tanks.

 

[Greg Hiller]

And also, in some cases out sand slowly dissolves, so the particles become smaller and smaller over time. This is particularly true in the lower pH zones below the surface of the sand bed.

 

[reefinghabit]

the tank at sea world had been set up for at least 8 yrs. i took it over about 1 yr ago. i did have some issues with corals not being 100% at there fullest potential.i sucked out as much of the old sand and waste that i could,then replaced it ,with 180 lbs of bahamas oolite. frequent water changes i think are good. 10% each week. at home i run a special grade reef sand 3-4" deep. i have seen undisturbed areas build up hydrogen sulfate gas.i beleive its a good thing to stir the sand, no matter how deep it is. every week. this helps release trapped detritus waste, also built up nitrogen gas,and keeps hydrogen sulfate gas from forming. also it keeps the levels of bacteria nitryfying and denytrifying continually transforming, waste into nitrate no3. at least thats my thoughts. my theory is proper sand bed maintenance and frequent water changes is a good recipe for success,in this hobby.

 

[Sean Irwin]

100% agree...As others have suggested, old tank syndrome is due (in part) to loss of biodiversity. Loss comes from depletion or failure of certain animals to reappear overtime, depletion of certain bioactive substances, and the selection of mono-cultures of microorganisms (like in old, unagitated sand beds).

 

[Dragon2115]

You won't be able to do this with the fine sand that is in most of our tanks without losing most of it down the drain. It works much better with the gravel that is used in most fresh water tanks.

I hear what you're saying Don but believe it or not I'm already doing it with the Fiji Pink. Come on over some time and I'll show you. Plus I do it to my FW tank as well which has that pita two-part substrate for plants in it. One part is the normal gravel but the other is that fine black stuff which is even worse than the Fiji Pink sand. Do I lose a little, sure, but the amount is so small it's insignificant. We'd be talking years before there'd be a noticable drop in the sand level. Is it a major league pita? Oh yeah. But that's why I don't do it that often.

Picture allowing the siphon to dig into the sand pulling a column of sand up the tube and then stopping the water flow before the sand reaches the hose of the siphon. Now wait until the sand settles back to the bottom and then restart the flow to carry away all the crud that just got stirred up and is trapped in the siphon tube. This is going to accomplish the same thing as stirring but without allowing all the nasties that reefinghabit talked about to circulate throughout the aquarium.

I think you and Greg differ on opinion from me because you guys are looking at it from the perspective of maintaining really large systems whereas I'm looking at it from the pov of maintaining much smaller ones. For you guys it just may not be as practical as it is for me. Plus, how much of the sandbed is accessible for cleaning is going to be a determining factor. In my tanks I can get at most of the sandbed (since my freakin dragon goby is determined to excavate every last grain of sand from under the rocks and place it against the front glass) whereas Don otoh can only get at a small fraction of his. I imagine Greg's tanks are probably the same way. So yeah, for you guys what I'm talking about wouldn't work. You guys are just in a whole different league than I am.

 

[Aquaman_68]

I think it can be done with a gravel cleaner. You have to have experience. I don't see a problem...Comon guys!! You know when you siphon the top layer because of of unwanted algae...You end up with sand in the bucket in the end!! I 'm sure with this w method & practice you will have less in the bucket in the end if you compare apples to apples