A Question On Gravel Cleaning

[Gruntle]

Okay, I must confess that it's been 3 months since I siphoned my gravel. But having said that, my fish are all healthy and the water parameters are fine, ammonia and nitrite are always 0, nitrate is almost always less than 40 (as soon as it's higher I perform a water change and filter clean).
 
Having read (and participated in) threads about cycling, I know that bacteria live in all parts of the tank, mainly in the filter and the top part of the gravel though.
 
It seems to me that siphoning the gravel stirs it up, moving the gravel at the top (where the bacteria are happy) to the bottom of the substrate (where they don't survive as well).
 
Would it make sense to not siphon the gravel at all? From what I've read, the cleaning is mainly cosmetic anyway, unless there's an overly large quantity of debris in it.  I reckon my plants appreciate the debris, they're certainly flourishing. If I continue the water changes to keep on top of nitrates, I can't see the harm in leaving the substrate alone, letting the plants grow their roots, allowing nature to take its course if you will. This would also allow the bacteria in the gravel to develop the necessary biofilm, and would avoid any issues through loss of bacteria through stirring up the substrate.
 
With appropriate feeding and appropriate water changes (and filter maintenance) I don't think touching the substrate is necessary, and could lead to a mini-cycle if the gravel was disturbed.
 
Please let me know if I'm wrong.

 

[Fishmanic]

I would still clean the gravel to keep the nitrates lower.   Most of the bacs live in your filter media.   Just rinse media in tank water.  Whenthe media is too clocgge or worn, don't change all the media at  once--just 1/4 at a time.

 

[KieranBoyne]

I'm with fm. Most of the bacteria breeds in the filter media, and of course some grows in the gravel, but i don't think its as much.

 

[TwoTankAmin]

There is a fair amount of bacteria potentially in/on one's substrate. the thing is we have not way to know where in a tank the most bacteria might be. There are a variety of factors which might determine this. However, there is a huge difference between what is going on in a well planted tank vs a very lightly or unplanted tank. It comes down to plants roots essentially.
 
In unplanted tanks, any aerobic bacteria (those which need oxygen) are limited to the top `/2 inch or so because as one gets deeper there is not enough O. As a rule planted tanks will have deeper substrate than non-planted and this is important in terms of the bacteria and cycling issues. Rather than regurgitate things, I will offer two looks. The first is a summary of a research paper in terms easier to understand and the second links to the paper itself for those who like reading that sort of thing.:
 
http/www.drtimsaquatics.com/resources/library-presentations/aquarium-hobby/aquatic-plants-nitrogen-cycle
 
https/wap.aslo.org/lo/toc/vol_42/issue_3/0529.pdf
 
In decently planted tanks the most one needs to do it to remove gunk that may be on the plants or excess gunk on the surface of the substrate- essentially cosmetic vacuuming. Do not disturb the substrate to any depth as it will be doing more harm than good.
 
Buy in the nonplanted tank this is more important. Any bacteria is near the surface and, as noted, turning it over is likely to have an adverse effect.
 
Pne last commetn, the bacteria lives where conditions are best for them. Depending on the media type, volume of media and then one's cleaning routine for the media, there can be a lot of not so much bacteria in one;'s filter. A tank will ultimately develop as much bacteria as is needed to handle the cycling chores. If the filter is not sufficient or hospitable enough, the bacteria will colonize elsewhere in the system.

 

[Gruntle]

Thanks for your replies, I'll continue the way I have been by just sucking anything I see lying on top of the gravel and leaving the rest alone.
 
Cheers.

 

[TwoTankAmin]

Sorry for the poor typing. But at the moment I am pretty much having to type with one eye closed due to some vision issues. I type badly enough with both eyes open, I have no chance at half power