i did a lot of research and i saw alot of threads talking about the benefit of the miracle or mineral mud.
can you please elaborate ? said:
The function of both is based on the same principle... the fine particles will house denitrification bacteria. The claims of the miracle mud and the like is that in addition to the denitrification, it also provides trace elements.
The base principle of a denitrification system is having a large enough volume or mass of fine particles (ala sand) to house enough bacteria, pods, critters etc to process the waste in the tank. In order for that to happen, you need to have sufficient volumes. In a 20g sump footprint, that is not possible as the populations will not be nearly as large as they need to be and it while it may be effective for a period of time, the amount of waste will overrun the population and then it becomes a sink for that debris. A sink is a depository for all the waste products that come down through the water column. Eventually the mud or sand will be saturated with it and start to be detrimental to the tank itself much in the way bioballs and drip/trickle filters do.
As far as trace minerals etc... you get all you need with a regular and proper water change. The salts we use provide ample amounts of them and you do not need to add any more.
If you combine not needing the trace minerals and the eventual breakdown of denitrification function, both sand and the 'muds' become useless alternatives over time.
On the flip side... if you dedicate that space to a macro algae and prune it consistently, you will pull as much of not more nutrients out of the system and not have to worry about it becoming a sink for the waste products over time.
You may also read about DSB's in a bucket etc... those are not true self-sustaining DSB's but basically sand filters or containers to trap the waste in an easy to disconnect and dispose of form factor. They work for a period of time, then they don't and start to contribute to the same problem they were put in to help out with.
The only way to maintain a healthy and long-term DSB is to have one of sufficient size and depth (volume) to maintain healthy populations of critters that can process the amount of waste your system generates. A 20G sump is not capable of doing that.
If you want to use the DSB method, I would suggest you increase the depth of the sand in your main tank up to a depth of 5 inches. A 55G will provide you with a large enough footprint. Just be careful how you stack your LR etc. You will want to seat the LR on the glass or raise it up above the bed with PVC or an acrylic rod structure. If you pile the sand around the LR you currently have in the tank, your DSB will still be effective, but about 30 to 40% less depending on your LR footprint. Sand under LR and even the LR itself under the sand loses its denitrification ability due to the loss of water movement through it etc.
