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Post by fishfever on Dec 7, 2009 22:42:29 GMT -5
I was reading Carl's article on hydrogen sulfide where he posted the article link on another thread and note that H.S. can be present below depths of 2.5 inches. So I guess with my typical substrate depths of 1 to 2 inches it's unlikely I'll have this problem, especially since I turn most of the gravel during vacuuming. But that leads me to wonder what an optimum (if there is such a thing) substrate depth is? I don't recall exactly what led me to use the depths I use; I think my wife objected to deep substrates because she didn't like the appearance. I do use a slight grade from one side of the tank to the other to encourage water movement (don't know if it really helps that much). I use a pea-size gravel in our 26g and smaller gravel in our fry and one isolation/hospital tank but all roughly the same substrate depth.
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Post by Carl on Dec 8, 2009 10:38:35 GMT -5
I should clarify that this depth also refers to #3 medium size gravel. With sand lesser depths and with pea sized gravel deeper gravel is required for sulfur reducing.
I am not sure if there is an optimum level, and the use of sand with plant roots often negates hydrogen sulfide production and encourages more nitrate reduction instead.
Water movement near the surface of the gravel can also affect sulfur reducing as well
Finally I have not found good scientific evidence of the dangers of hydrogen sulfide, mostly just anecdotal observations (including mine since i have not been able to perform controlled tests on this subject).
Carl
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Post by fishfever on Dec 8, 2009 18:28:17 GMT -5
Thanks Carl. I don't think I ever gave much thought to what the optimum depth should be so I just chose the 1-2" depth. I don't have live plants so 1-2" seems to be about the minimum depth to cover/hold the plastic plant bases down...
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Post by babygeige on Dec 12, 2009 11:12:59 GMT -5
This tank that I'm trying to save has over 3 inches of gravel on one side. I don't know how it is for the hydrogen sulfide, but I'm with your wife. It doesn't look as good, especially when it's not cleaned. It looks super black and icky.  I've got about 2 inches in my 10 and 30 gallons. It's just right for my plants. |
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Post by corycatwoman on Dec 12, 2009 13:02:04 GMT -5
depending on the fish in the tank. and the plants you have in the tank.
but for general purpose which this situation is i would say roughly anything more than 1/2 inch and definately less than 2 and 1/2 inches.
hopefully that helps.
if theres plants or digging fish i would suggest closer to the max on depth. if theres just plastic fake fish and free swimmers that dont mess with the gravel. 1/2 inch would be ideal.
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Post by fishfever on Dec 12, 2009 13:45:44 GMT -5
At about 1/2" I've found that the plastic plant buoyancy tends to lift up a bit too much unless I mound a little hill of gravel around it, sort of like you see with trees and mulch... But at around an inch or so (or more) I can keep the gravel around the plant fairly flat while still holding the plant down. I guess I could probably attach some sort of weight (maybe tie a large flat rock with dental floss) to plant bases to get away with less gravel. But I have cories in my 26g, so the slightly deeper substrate probably works better for them.
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Post by Carl on Dec 13, 2009 11:12:13 GMT -5
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Post by Suzie Q (Lori) on Dec 16, 2009 11:18:46 GMT -5
I have most all of my tanks fully planted. on 1 10g I have about 1.5 inches of soil...plant roots come to the surface...my 55g has 3.25 inches and the roots stay buried. My other 10g (at home) has probably 2 inches and the roots stay buried. I feel that live plants need deeper soil. I have my 75g that has yet to be changed to soil...it has I think 3.5 inches of gravel in it. I only have Java Fern and Hornwort in it (and some Java Moss that the SAE eat). I will probably put 4 inches of soil in it once I switch to that. I also believe the larger the tank...the deeper the soil can be. I just clean really good with my WC.
Lori
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Post by kagome on Dec 17, 2009 0:10:38 GMT -5
Ok, this is going to sound so lame, but I literally put gravel in until it "looks right" to me. And please, for the love of kittens, don't ask me to put into words what makes it "look right". I don't have live plants, mostly b/c my husband complains that they are such a huge pain to take care of. Anyhoo, after I have the tank set up I gauge whether the gravel is too deep or not by how easy or hard it is to get a gravel vacuum of an appropriate size to reach the bottom of the tank since I vacuum all of the gravel with each water change.
I freely admit that this is the most unscientific and unspecific method offered so far but I thought I would just throw my two cents in there. After seeing this thread I did go measure and I have just over one inch in the 20g and about one and three quarters in the 38g.
My gravel level process made me think of when people ask me for my marsala sauce recipe and I have to grimace and say "Uh well, I make a rue and cook it to where it's just kind of thick but not really thick, then I throw in shallots until it looks good, then I pour wine in until it looks good, then I add chicken stock until that looks good, then I set it on fire for a few seconds and reduce it down until it looks good. Then salt and pepper to taste" I know, scary isn't it? But even if I can't tell someone exactly how to do it at least I can get it to come out right when I do it. (Sorry to get off topic, the gravel thing just reminded me about how I just wing some things and somehow it works out)
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Post by Carl on Dec 17, 2009 10:17:34 GMT -5
When it comes to the "exact" amount of gravel, I personally think winging it is just fine, especially since many variables go into this, from vacuuming frequencies, to size of gravel (this makes a big difference in depth as larger diameter gravel can be much deeper before sulfur reduction begins), plants or no plants (another major factor), even how much mulm/sludge is accumulating.
You can also use the "unscientific smell test" by scooping out some gravel and "sniffing it". If it smells like a rotting wet rug, or worse; like a rotting egg you have gravel issues (although not necessarily depth)
Carl
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Post by Suzie Q (Lori) on Dec 17, 2009 12:22:58 GMT -5
When it comes to the "exact" amount of gravel, I personally think winging it is just fine, especially since many variables go into this, from vacuuming frequencies, to size of gravel (this makes a big difference in depth as larger diameter gravel can be much deeper before sulfur reduction begins), plants or no plants (another major factor), even how much mulm/sludge is accumulating. You can also use the "unscientific smell test" by scooping out some gravel and "sniffing it". If it smells like a rotting wet rug, or worse; like a rotting egg you have gravel issues (although not necessarily depth) Carl I totally agree Carl!!! Kagome....I LOVE IT!!! I make chocolate pies about the same...I do have a set recipe but the cooking time is where im like...ummmmm I just cook it till it looks right...or sets up in the "cooling" spoon right...people are like...OK but HOW LONG?...LOL!!! |
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