Freshwater and DSB

[jeffp]

Has anyone here tried doing a deep sand bed in their freshwater tank? I was reading about them and it really interests me, but it seems that there is just not a lot of information about it for freshwater.

 

[Tigroscr]

Yeah! I just did one using flat river rocks @ the bottom of the tank and then layering the sand over them to make it deeper. Is that what your talking about?

 

[jeffp]

I'm talking about sand that is like 3 inches deep and not mixing it up or disturbing it so the bottom of the sand becomes anaerobic and anoxic. These zones then harbor bacteria that can extend the nitrogen cycle to turn nitrates into nitrogen gas. That way, you don't have to vacuum the substrate (the food and poo get broken up and mixed into the sand to feed the bacteria), you don't have to fertilize your plants (the process of turning nitrates into nitrogen gas creates nutrients that the plant uses), you don't have to dose CO2 (same as nutrients above), and you don't have to worry about nitrates building up.

 

[jcolon]

There was a thread a few months back where someone researched anoxic zones in sand and determined that a few inches of sand may not be deep enough to establish much if any anoxic zones. The worry was that while mixing up the sand during a gravel vac ... some anoxic gases could be released into the water and kill the stock.

It is an interesting idea if it can be done in an aquarium ... and if 3 inches of sand's deep enough. I would think you'd need really fine sand like play sand ... PFS is probably too coarse and would allow more water flow.

Waiting to read about experiences from members ....

 

[Tigroscr]

I found this link to be helpful for me regarding what type of sand to use http://www.cichlid-forum.com/articles/pool_filter_sand_pt1.php

 

[jeffp]

There was a thread a few months back where someone researched anoxic zones in sand and determined that a few inches of sand may not be deep enough to establish much if any anoxic zones. The worry was that while mixing up the sand during a gravel vac ... some anoxic gases could be released into the water and kill the stock.

It is an interesting idea if it can be done in an aquarium ... and if 3 inches of sand's deep enough. I would think you'd need really fine sand like play sand ... PFS is probably too coarse and would allow more water flow.

Waiting to read about experiences from members ....

I only found one good thread on this at aquariacentral and an article written by some guy, and they were both quite successful at getting the cycle to go through to nitrogen gas. Several people in the AC thread also said that they had luck in getting it to work.

As for the toxic gas, the idea is that you don't have to vac it because the detritus will settle on the sand and get worked in by MTS and blackworms, which can rot and feed the bacteria in the anaerobic zone. And if you do have to vac the sand, don't mix it up and vac an inch away so it can suck up the stuff sitting on the sand without moving sand.

 

[jeffp]

Well, I'm gonna give a deep sand bed a try, going off of the information in the aquariacentral thread I found. Will be putting down a 3" sand bed of PFS. Several people have had good experience with using PFS so hopefully it works for me too. Will be planting and doing DIY lighting in the next 2 weeks. I'm hoping that I am lucky and everything works out so that I end up with a nearly maintenance free tank.

Also, does anyone know where to buy blackworms from? Somewhere that doesn't sell them in 1 lb packages and the like. Just need a few tablespoons worth

 

[jcolon]

I only found one good thread on this at aquariacentral and an article written by some guy, and they were both quite successful at getting the cycle to go through to nitrogen gas. Several people in the AC thread also said that they had luck in getting it to work.

As for the toxic gas, the idea is that you don't have to vac it because the detritus will settle on the sand and get worked in by MTS and blackworms, which can rot and feed the bacteria in the anaerobic zone. And if you do have to vac the sand, don't mix it up and vac an inch away so it can suck up the stuff sitting on the sand without moving sand.

Yep ... I figured there has to be successful attempts ... thanks for the followup. As for the toxic gases ... the same guy that did the research did mention that any produced would probably be in too small a quantity to harm the stock should they be released during gravel vacs. On that I'd like to hear any other supporting evidence.