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is my substrate OK?!

5605 Views 29 Replies 11 Participants Last post by  Alex123
hey guys,

i'm a little worried that my substrate has gone bad! the fish and plants seem fine, but whenever the substrate is disturbed it is quite bubbly! NO2, NH3, and PH are all normal. this is my Walstad 20g and has been up and running for about a year. hmmmmmm
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The fish have already stopped glancing and ate very exuberantly today, compared to yesterday.

I thought i'd share something of interest, which relates to an excellent thread from about a month ago about choosing soil types. I totally forgot that i had set up a bottle test using a some of the soil i had left over from my original set up. I air dried it then submerged a small handful of the soil in a medium sized jar 2 1/2 weeks ago with the lid loosely sitting on top. I also changed 75% of the water twice after it had settled before leaving for Christmas holidays. I opened it today and it was a little bubbly and it absolutely reeked of rotten eggs. This leads me to believe I picked some bad soil to begin with.

So here are my queries - hopefully a science buff or actual scientist will weigh in here for me...
-Does the presence of hydrogen sulphide gas mean that this particular soil has an excess of sulphates to begin with?
-Is it possible that soil that is high in sulphates is more sensitive to going bad, or do all soils have lots of sulphates and it is solely the anaerobic conditions that make it 'go bad'?
-This is my last question, I promise: What chemical is it exactly that is bad for your tank in this case; the suphates, the hydogen sulphide gas, or a byproduct?
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Here is something I read about anaerobic:
Anaerobic means lack oxygen. All substrates are anaerobic including gravel. The mud that plants grow in, in nature, is also anaerobic. Plants deal with this by forcing small amounts of oxygen through the roots. This allows for aerobic types of good guy bacteria to grow around the roots.
H2S is the bad gas and also the gas that smells like rotten eggs. It is present in all soils. It takes some oxygen to cure it. Bacteria will reduce the H2S if they have oxygen as a nutrient. Plants will release O2 into the soil to help this process. If you have a section of your aquarium that is prone to H2S then planting an emergent plant there should cure your problems. An emergent plant will have good O2 reserves and grow its roots quickly.

Sulfates are part of all water and are not a problem.
so, it's the bubbles themselves that are bad! that was my suspicion. - and anaerobic conditions can make any soil go bad! good to know. i have been stressing about which soil to use in my next tank, but i will not worry so much and spend more time planning the aquascape to include heavy rooters and emergent species. i'm sure some soils are better than others but as long as the soil you choose follows the guidelines recommended in Diana's book and by others on this forum, it will be fine.
so, it's the bubbles themselves that are bad! that was my suspicion. - and anaerobic conditions can make any soil go bad! .
Not all bubbles are H2S, which gives off the egg odor. If the soil has becomes very anaerobic, do to lack of oxigination, it will release H2S bubbles.

According to colinsk bacteria will reduce the H2S if they have oxygen as a nutrient. Thus perhaps poking the dirt, then doing water change, and then adding bacteria will help. You can add bacteria with API Stress Zyme+Biological.
Just a note on this subject. I have 2 NPT in the house now. The first one I did I didn't sift the home depot top soil. That tanks water yellowed up over and over like tea overnight. the bubbles from the substrate would sometimes take the soil though the gravel cap while poking at it with a chopstick to relive the pressure. After six weeks or so it calmed down. For a long time I thought the experiment tank was not going to turnout right. Then it just started to run great on its own, generates very little bubbles now. Then my daughter was so impressed she wanted to redo her tank. So i used the same soil that was leftover from the first tank. We sifted the soil so no wood chips this time and used seachems fluorite black sand to cap it instead of the gravel I used on the experiment tank. This time the tank broke in at about the 3 week point almost no yellowing of the water and very few bubbles. I am happy with both tanks but how you set-up the tank even with the same materials makes a huge difference.
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Yes, i agree - this time I will air dry the soil and then sift it. My tank has been up for a year now and the water still yellows! I'm also planning on using a thin layer of quartz sand as my soil cap - i think that will be easier for the MTS to dig into and the soil will stay more aerated. Many people are having great success with this including Diana herself. Also I think my kuhli's will enjoy the sand more! I may even include a sandy "beach" area with just a thin layer of sand just for them. Also I'm using a more shallow tank, 16' tall instead of 20', so i know i'll be able to get better plant coverage over whole of the substrate and have better luck with carpet and foreground plants. I even thought of going with a 20 long, but then I thought I would miss having my tall plants.
I'm also planning on using a thin layer of quartz sand as my soil cap
Beware the sand will collect mulm and it is impossible to vacuum up. My first tank had sand over the whole substrate. After 3 months I came to hate it. Now I have a 29 gallon tank with sand in the foreground and fluorite on the rest. Used metal sheets and rocks to divide the 2 substrates. No mulm is on the sand. Just a few pebbles of fluorite are.
Here is the latest update on my substrate - I think I cured it! (mostly) I hadn't done a soil poking in a couple of weeks and when I did it was almost completely bubble free! So for those having the same problem as me: it's possible to reform your rotten substrate by heavily planting and manual aeration. But I'm still planning on starting fresh - I already bought my new tank and have almost completed planning it. I've decided on starting a 20long which I'm excited about. I'll be setting it up over the next month so I'll keep you posted. Thanks all!
Rusalka, enjoy your comments and enthusiasm. I hope you can provide more pictures! I love pictures. I bought topsoil form home depot. Never have this yellow water ppl mention here. I take a little effort to remove most of the larger wood chips. I do notice that my trumpet snails will push out the rest of the larger chips later after I setup the tank. One thing I am definitely going to do for my next tank setup is mineralized soil substrate. This should help greatly reduce the new tank syndrome. The concept is basically soak the soil in water for a day. Pour out the water and spread thin the wet soil on a plastic sheet and let it dry a day or longer. Repeat a few more times. This drying process oxygenates the soil, gets the microbes going and ultimately mineralized the nutrients in the soil. Sounds like a fun idea to try and have a proven record so they say.
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