# How bad are anaerobic sections if I cap MGOPM with PFS or sand?



## DogFish (Jul 16, 2011)

I feel this is an over hyped point of concern.

If you use a good cap, keep MTS(Snails) and rooted plants it is not an issue. If anyone on this site should have a problem it it would be my Toxic Ten tank...Into my 2nd month no problems :wink:

I'd be much more concern about dead space under rocks or drift wood.


----------



## HD Blazingwolf (May 12, 2011)

i have had a few toxic spots in my dirt tank. i could poke it every day and get deathly aweful smell. rememdy? put plants in bad spots.. roots provide oxygen.. oxygen provides means for aerobic bacteria. anaerobic dies


----------



## freph (Apr 4, 2011)

My soil/sand is like 4" thick and I have a few bubbles every now and then but that's it. No death smell, though. I've also got a very healthy MTS population. I wouldn't worry about it.


----------



## Robert H (Apr 3, 2003)

What the heck is PFS? MGOPM?

Putting plants in Anaerobic areas doesn't solve the problem. An Anaerobic area will turn the plant roots black and kill the roots. If the plant is not able to establish new roots, the plant dies.

Having a "cap" makes no difference. A cap only buries the decaying organic material deeper so it takes longer to reach the surface of the gravel.The substrate can have anaerobic areas if its a foot deep or one inch deep. 

An Anaerobic area of the substrate is from decaying organic material which sucks up oxygen. The cure is to not have decaying organics in the substrate: soil, peat, plant leaves, fish poop. If you stir up the gravel to allow air in it, that helps, but is difficult to do in a planted tank.

The other option is to vaccum the substrate. Not such a good idea with soil in there. Limiting leaf litter helps. Remove decaying leaves before they get into the substrate or turn to dust. Vaccum the surface of the gravel regularly, and vaccum the "cap" above the soil layer at least.



> I feel this is an over hyped point of concern


I agree that anaerobic areas happen in any aquarium. with or without soil. But in tanks without soil, its easier to treat the problem... just deep vaccum the area pulling out the trapped areas of garbage that is causing the problem. Its also possible to live with these areas and go on... but eventually those areas spread to be worse. I would rather deal with it while its a small problem.
And BTW, the benefit of burrowing snails is way over stated. They actually do not burrow very deep into the substrate at all. Usually not much deeper than to barely cover their shells, and they do not move any great distance. I have snails in anaerobic substrates quite frequently.


----------



## VeeSe (Apr 16, 2011)

Robert H said:


> What the heck is PFS? MGOPM?


PFS = pool filter sand

MGOPM = Miracle Gro Organic Potting Mix

There is also MGOCPM which is actually what I was thinking of in my head when I posted, and that's Miracle Gro Organic Choice Potting Mix.


----------



## DogFish (Jul 16, 2011)

Robert H said:


> ....Putting plants in Anaerobic areas doesn't solve the problem. An Anaerobic area will turn the plant roots black and kill the roots. If the plant is not able to establish new roots, the plant dies....
> Having a "cap" makes no difference....An Anaerobic area of the substrate is from decaying organic material which sucks up oxygen. The cure is to not have decaying organics in the substrate: soil, peat, plant leaves....And BTW, the benefit of burrowing snails is way over stated. They actually do not burrow very deep into the substrate at all. Usually not much deeper than to barely cover their shells...



That all sounds so convincing until you see this tank:










I believe it violates every point you offered :biggrin:
http://www.plantedtank.net/forums/tank-journals-photo-album/154884-toxic-ten.html

Which is exactly why I set it up.


----------



## Robert H (Apr 3, 2003)

LOL... troublemaker! Beautiful tank! Like I said you can live with anaerobic spots, and apparently you do it very well! :smile: That is if you have anaerobic spots. Maybe you don't! Maybe you just have stinky water! :icon_eek:

I wouldn't use sand unless it is a very course sand. You don't want it to compact. That would make it go anaerobic even faster... right Dog? The main thing is you want oxygen to reach deep into the substrate. The reason for a "cap" layer over the soil, if cap is what you want to call it, is to keep the soil from getting into the water. Its not to seal in methane gas. A clay gravel would be better than sand because it is porous and holds oxygen as well as minerals. Sand has no minerals and cannot hold oxygen.



> 2nd month no problems


WAIT a minute, I just noticed this. You are judging your success with only going two months? Two months is nothing! Bro, seriously. It can take a while. It can take months for some organics just to decompose. Its doubtful you have any anaerobic areas yet. Give it six months to a year


----------



## DogFish (Jul 16, 2011)

"I wouldn't use sand unless it is a very course sand. You don't want it to compact."

> I use a mix of sand from very fine to 1/8"-1/4" grains. This is simply construction sand that I rinse clear. I would say however, 70% is fine sand

"WAIT a minute, I just noticed this. You are judging your success with only going two months? Two months is nothing! Bro, seriously."

> I'll run this experiment for 1 year. Of course people will say at one year, "It can take Years for some organics just to decompose. Its doubtful you have any anaerobic areas yet. Give it 2 to 3 years"

If I had a better camera, it's clear that the green material, grass/weeds are gone in the substrate, I was purposeful in having some of that near the glass. There are very black areas under the sand which may or may be Anaerobic.?? There are several color changes in the substrate. I will try to take picks to update the thread.

"Like I said you can live with anaerobic spots, and apparently you do it very well! That is if you have anaerobic spots."

> Nice Back peddle :icon_roll

"Maybe you don't! Maybe you just have stinky water" 

> There's no exceptional oder, it smells the same as all my planted tank. Interestingly, it's my Coffee Bowl project that smells. That is still in dry start.

"A clay gravel would be better than sand because it is porous and holds oxygen as well as minerals. Sand has no minerals and cannot hold oxygen."

> I've seem this type of a statement used in many of these discussions. The sand contains the dirt for the sake of the viewer of the aquarium. The plants don't care and neither do the Inverts & Fish. When I've moved plants in that tank, the shrimp will swam to the place were I've disturbed the cap. 

the 2nd function is to give a good anchor point for new roots. More important with plants with delicate roots.

"LOL... troublemaker!"

> I built this tank to challenge the some of the "rules". Many of which you have presented in your posts. Most of which, logically don't make any sense to anyone that has ever seem any aquatic plants grow in nature. 

" Beautiful tank!"

> Thank you, not a lot of thought was given to Aquascaping. I wanted a wide variety of plants. They were placed somewhat by need light/water movement and growth potential. most are cuttings & ROAKs. Some babies from my other tanks.


----------



## monkeyfish (Jul 5, 2010)

DogFish said:


> "I wouldn't use sand unless it is a very course sand. You don't want it to compact."


PFS is screened so you end up with a uniform grain size, it doesn't compact like regular sand. There are a lot of people here who use PFS with no issues. Myself included.

Sent from my Droid using Tapatalk


----------



## DogFish (Jul 16, 2011)

monkeyfish said:


> PFS is screened so you end up with a uniform grain size, it doesn't compact like regular sand. There are a lot of people here who use PFS with no issues. Myself included.
> 
> Sent from my Droid using Tapatalk


You are actually responding to Robert H, I was quoting and responding to him.


----------



## wkndracer (Mar 14, 2009)

*Vacation*

haha, with family visiting and holidays I've been off the site longer than anytime since I joined. Enriched substrates are the topic of a number of recent posts and that has me smiling. :smile:

Robert, little surprised by you're position on organics within a substrate stating the need to remove or eliminate them. Decaying organic material deep in the substrate is exactly why I feel most of my tanks work so well over time. Also why I've chosen Miracle Grow Organic Choice Potting Mix for most of them. Another factor was the poor content of the local soils where I'm located.
Unlike Dog's poo tank I have systems setup and established at various ages up to the oldest which is just shy of three years flooded that closely follows the Walstad method. Problems only started, if the situations could be classified as problems after the majority of the organics were consumed by bacteria in that tank. 

From fine grain coal slag (blasting media) comparable with PFS to Flourite original the 'cap' (for me) is to add overall depth along with containing the lighter materials like wood chips, bark and leaves (organics) as that is the major material of the potting mix starting out.

Further splitting hairs on the topic, isn't Anaerobic and Aerobic type bacteria present in all substrate with only imbalance or larger pockets creating the 'problems'? I have to ask because having had black stinky pockets in one tank or another I've never had anything die due to it except for a few Reopen stems. Later poking around and replacing plants the areas of issue were eliminated over time without any real drama.


----------



## monkeyfish (Jul 5, 2010)

DogFish said:


> You are actually responding to Robert H, I was quoting and responding to him.


You are correct dog, my bad. 

Sent from my Droid using Tapatalk


----------



## Higher Thinking (Mar 16, 2011)

Now whether anaerobic spots are really bad or not, I don't know. What I do know is that I have them in some of my tanks and they don't seem too problematic. Except if you consider that the layer of substrate that is allowing this to occur is obviously not permeable to fresh oxygenated water so heavy root feeders will not grow well as they do not receive new nutrient enriched water. This is something I am dealing with regarding a compacted layer of sand over gravel.

Also, and more importantly, do some research and you will discover that plant roots TAKE IN oxygen in order to survive. So placing them in anaerobic spots isn't solving anything. If perhaps aquatic plant roots also GIVE OFF oxygen, I don't know, but given that I have found sources which state that aquatic plant roots take in oxygen it wouldn't make sense for them to give off oxygen as well. If someone finds information to the contrary by all means bring it to light


----------



## Robert H (Apr 3, 2003)

Back peddling? I am not back peddling, just trying to be polite. You can't judge anything on two months. But what exactly are you trying to prove? Its simple science. Same principal as a compost pile. Organic material decomposes. As it decomposes it uses up oxygen. When there is a lack of oxygen it is anaerobic. Plant roots turn black and begin to rot if they are in the middle of the decaying organics and getting no oxygen. When a substrate is compact it compresses the organic material and blocks the flow of oxygen. The same thing happens in terrestrial gardening, indoors and outdoors, potted house plants, and hydroponics.

In hydroponic gardening, plant growth is excelarated by a nutrient solution that is very high in oxygen around the roots. In static hydroponics, an air stone is used. In current hydroponics, a moving current of water brings a continuous supply of oxygen to the roots. In house plants, perlite, vermiculite, and other mediums are used to aerate the soil and prevent compacting so the roots do not become anaerobic. 

Why would an aquarium be any different? The worst case scenario is a totally anaerobic substrate would emit toxic gas that would be poisonous to fish and plants. Has it ever actually happened? Not that I know of, but it is always suspect. The closest I ever came was in my first "planted" tank years ago when I had peat plates under the substrate that went completely anaerobic. The plates were solid black and smelled like rotten eggs. It was rancid and fowl. I had several fish die off and it was a complete mess. Most of the plants kept growing except the ones that were directly over the peat. I ended up teraring it all down and starting over.

There has been tons of documented discussion about this for 20 years or more.

Anaerobic areas also come and go. You can loosen them up, plant around them and take steps to minimize their affect. If you could prevent it or minimize it by simple maintenance, why wouldn't you want to do that?

All substrates can compact over time. The finer the particle, the quicker it will compact. Substrates can also get root bound, just like a potted plant. But not in two months. 

People have been fine tuning substrates for decades. Why not learn from it instead of ignoring it.

Yes, plant roots go through photosynthesis, and so do bacteria in the substrate, they both use and emit trace levels of both oxygen and C02, but in the absence of oxygen they can not survive. Its just like if your water looses all its oxygen, which isn't that hard to do. No oxygen in the water plants will die, as well as fish.

Look up the term DOC. Dissolved organic compounds. The higher DOC levels become in the water, the lower the oxygen level the more dangerous it is


----------



## DogFish (Jul 16, 2011)

Robert I've shown you a tank that refutes your pontification. That is actually what I am "Trying to Prove" by setting this tank up. I didn't set it up for the approval and delight of the "Roberts" of the aquarium hobby. I set this up to help the newbies. At this point there is really no reason to continue a conversation and I am being very polite in my response. 

:wink:


----------



## madness (Jul 31, 2011)

There are a lot of people using the Walstad method (or variations of it) with success (both long and short term).

Regardless of what the chemistry involved might be it seems sort of silly that people are still running around screaming about the sky falling if a substrate has a small amount of organics in it when there are well documented examples of tanks that avoid the cited problems.


----------



## anh (Jul 20, 2009)

i honestly believe the problem of anaerobic section are overrated, i had my tank running a year with heavy root feeders such as marsilea, crypts and swords and NEVER had a problem with root rot. Now when i re scape my tank the organic stuff gets pull to the top of the water but doesn't float up, only cloud the water slightly and settle down. I was also able to form a dense full carpet.

I use potting soil cap with kitty litter cap with pool filter sand.


http://www.youtube.com/watch?v=3Ze7A5k2Rw0

you'll be the judge


----------

