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Hi all,

I'm having a bit of a problem with my sand substrate going anaerobic in my current tank. The sand is about an inch deep and is Unipac Silver Sand bought from my LFS which I thought would have been a good choice...I am about to start another tank and would like your thoughts on different types of sand, I know some people use childrens play sand but does anyone have any experience of BD Trading Aquarium Sand or the Caribsea Tahitian Moon Black Sand? The BD Aquarium Sand says it won't compact which I guess is the cause of my anaerobic problems now...

The current tank is home to corys as would the new tank be, hence the focus on sand.

Regards,

Andy

You can avoid aneorobic buildup by either having a fairly thin layer of sand, thus allowing oxygen through to the bottom of the sand (and the corys to stir it up enough to not cause a problem in the first place).

I'm not sure any particular type of sand is any better than any other sand - other than looking slightly different.

Small grain size is the real problem causing aneorobic buildup, because the water doesn't flow through the sand to supply oxygen, and thus bacteria that doesn't use oxygen will start living in the sand.

There are some fish (and other creatures) that constantly move the sand about, that would also be an option. Eartheaters, kuhli loaches and such would be one suggestion that may work to stir the sand about. Of course, if you're trying to breed your cories, they may not work as they are likely to eat the eggs... Can't win all the time...

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Mats

Thanks Mats, I have thought of putting some Kuhlis in. I'm not too fussed about the cories breeding in this tank as I have successfully bred them in a small 30 litre tank.

Someone has suggested that a substrate heater cable such as the Rena Cor cables causes convection currents at the bottom of the tank pulling oxygenated water through.

Althought the tank is not "heavily" planted, there are a few types of Hygrophilia growing so I guess it's a trade off between enough sand for plants to take root and not to much to go bad were the plants don't have any roots...

Andy

An alternative to using just sand is to mix sand and gravel, so you have areas that are sand and other areas that are gravel, allowing you to plant in the gravel areas (where you can stack it high) and keep the sand for the "cory play areas".

Obviously, some sand will leak into the gravel and vice versa, but it may be better than the current solution.

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Mats

I guess it's a trade off between enough sand for plants to take root and not to much to go bad were the plants don't have any roots...

You can also place the plants in planters. I just cut the bottom 3 or so inches from a small water bottle, fill it with a sand gravel mix, and put the plants in it. Then you can keep the sand substrate and have some plants. A few well placed stones and driftwood pieces will easily hide the clear planters made from the water bottles.
-Shane

It's quite a feat to get a 1" thick layer of sand anaerobic, even fine-grained sand... Do you have any circulation at all in the tank? How do you know there are anaerobic zones?

Anyway, my suggestion would be to ask around for malaysian tower snails. They're prolific breeders and tend to become a bit of a pest, but they *will* keep your 1" sand bed well stirred & aerated, and they do not eat fish-eggs or bother plants.
Also improving circulation will likely remove any anoxic zones in that shallow a sandbed.

Cheers for that Shane, I might give that a try.

Hi Mike, the tank is a Juwel Delta 80 which if you are not familair with is the forerunner of the Trigon tanks. Circulation is from a Fluval 305 with the outlet in the back corner pointing left and the inlet in the front right corner. What tends to happen is that sand builds up on the right hand side and debris seems to build up in it leading to pockets of black smelly stuff....So it starts out as about 1 inch....

Thanks for the heads up on the snails, I don't know why but I've never really liked the idea of having them...

Andy

The type of snail which buries itself in the substrate, the long shelled variety commonly encountered in aquariums is definately the way to go. My lfs always has loads lurking in among the plants they sell. They will happily live under the sand and constantly move it around, I have them in all of my tanks with sand and never have anerobic problems....

The guys are right on about the Malaysian snails they will also eat the minute particles of left over food that is contributing to the anaerobic zones. No excess food and substrate O2 and the sulpher reducing anaerobic bacteria will disappear. They are extremely utilitarian additions although it is hard to understand the sand going bad unless there is an excessive amount of uneaten food particles. I use the same fine grain sand 1 inch deep and only have pedestal sponge filters and don't ever have the problem you describe. BTW the Black "Tahitian" sand appears to be nothing more than an ordinary sand blasting sand which is very cheap. You notice how they make it clear that it has little or no reactivity with the water. That's because its sand blasting sand sold at 10 times what it's worth.

Get one of these, an Geophagus Iporangensis



It will keep the gravel fully stirred up and will not touch corys, mine is 7" and lives with 3 Rainbow fish about 1" long and 3 Plecos also 1" long,

Warning, it will kill all tetras for some reason (Natural food i know), does not matter what type but i had 30 tetras go over night!!! any other fish and your ok, Oh it also hates plants A LOT!!!,

If your happy with your tank tipped upside down every 2 days,

ITS THE FISH FOR YOU!!!

Or if you have no plants just run your fingers through it once a week at water changing time.