What is the point of organic potting soil for mts?? - The Planted Tank Forum
LinkBack Thread Tools Display Modes
post #1 of 6 (permalink) Old 06-28-2012, 04:49 AM Thread Starter
Algae Grower
PTrader: (2/100%)
Join Date: Dec 2011
Location: St Louis
Posts: 71
What is the point of organic potting soil for mts??

Could someone explain to me the reason everyone buys bags of topsoil with organic matter in it and then decomposes it?? I am thinking about putting some dirt in my tank and don't see why I should pay for dirt when I have a bunch in my yard and garden.
Secretninja is offline  
Sponsored Links
post #2 of 6 (permalink) Old 06-28-2012, 11:50 PM
Wannabe Guru
PTrader: (0/0%)
Join Date: Jun 2011
Location: NJ
Posts: 1,458
Several reasons, but bascially draws down to knowing what you're buying vs. what you don't:

1) Pesticides or toxic solvents in soil or drainage from other lawns, cars, even plants.

2) Unknown Parasites

3) Unknown chemistry, garden soils have additives for outdoor plants, such as cow/pig manure.

4) Unknown mineral content, mercury, heavy metals, such as copper or lead, chromium.
AirstoND is offline  
post #3 of 6 (permalink) Old 06-29-2012, 01:36 PM
Planted Tank Guru
PTrader: (0/0%)
Join Date: Jan 2010
Location: Contra Costa CA
Posts: 11,721
Organic means 3 things:
1) Derived from living matter (Plant or animal material)
2) Composed of molecules that contain at least one atom of carbon (Chemist's definition)
3) Some fuzzy definition of not-man-made.

Buying "Organic" potting soil is sort of buying into the hype of the word "Organic" (definition 3), but it does mean something in this use. Non-organic potting soil may have fertilizers, water retaining polymers and other things that we do not want in the aquarium.
Specifying a particular brand name gets us all onto the same page in that many other people have used that product for aquariums. Most often they are talking about Miracle Grow Organic Potting Soil. I am sure there are other materials out there.
"Topsoil" is another catch phrase that means different things to different people (including the manufacturer!). When you buy it in bags the goal is that you are buying the mineral portion of the soil (sand, silt and clay) with a minimum of organic matter (definition 1).

You can use garden soil. Just take it from a place that you know has been free of toxins for enough years that whatever may have been there has been broken down. A fairly active (micro and macro soil organisms is a good sign)

Then check that soil for the ratio of sand, silt and clay. If you want, I will post the instructions.
Add as much compost (organic matter, definition 1 and 3) as you want, but avoid the chunks that you can still identify. You want the finest, dust sized particles. If you make your own garden compost, I would screen it though hardware cloth to make sure you have only the smallest particles.

When you have the materials you want, mineralizing is optional; it is sort of like aging the materials faster than if they are submerged in the tank. You could put the material straight into the tank, then monitor the conditions. Some soils product a fair amount of ammonia for up to a month when they are first placed under water. This may be OK for plants (go ahead and plant the new set up) but is of course not good for livestock. The ammonia production is a good way to do the fishless cycle in the tank.
Diana is offline  
post #4 of 6 (permalink) Old 06-29-2012, 05:45 PM
Planted Member
PTrader: (10/100%)
Join Date: Jun 2008
Location: Orange County, CA
Posts: 281
I don't think you are supposed to use organic potting mix with MTS. If you were putting the soil straight into the tank, then yes you would use something like Miracle Gro Organic Potting Mix. But if you are going to mineralize the soil, you are supposed to use super cheap topsoil that does not have organic matter, plastics, etc.
Soujirou is offline  
post #5 of 6 (permalink) Old 06-29-2012, 05:58 PM
Planted Tank Guru
PTrader: (33/100%)
Join Date: Jul 2011
Location: Gone
Posts: 5,994
[QUOTE=Secretninja;1920504]Could someone explain to me the reason everyone buys bags of topsoil with organic matter in it and then decomposes it?? ..../QUOTE]

Pretty silly waste of money. If your are going to build MTS you can use Home Depot 40# TopSpoil @ $1.17 a bag or catch the sale for 87cents a bag.

The expectation that "organic" dirt is QA tested by the the bag is nieve at best.
DogFish is offline  
post #6 of 6 (permalink) Old 06-29-2012, 06:59 PM
Planted Tank Guru
wkndracer's Avatar
PTrader: (68/100%)
Join Date: Mar 2009
Location: Citrus County,Florida
Posts: 6,186
Where I live in Florida we call it 'the sand hills' because the soil is very poor on content for plant growth. I use a mix of topsoil with lots of organic matter in it and let it decompose if thats the word of choice in tank where all the minerals and gasses from the bacter mineralizing is used by my plants.

Submerged decay or decomposition happens in nature all the time.
Works very well in my tanking systems too.

Reposted my opinions on this topic in a very similar thread today.

I did one mineralized tank here but have repeated the NPT setup well over a dozen times with high ratios of organic content in the substrate. With 24 currently flooded tanks they all are one time builds, meaning I've yet to achieve failure on a system requiring reset.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

If at first you don't succeed,,, keep kicking it
2-75g planted, 3-55g planted, 110g w/30g sump, 2018 update returning to sanity (Nutz)
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
wkndracer is offline  


Quick Reply

Register Now

In order to be able to post messages on the The Planted Tank Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome