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Discussion Starter · #1 ·
Hi all.

I was wondering if anyone has experience having large rocks placed on top of their dirted tank setup.

I've been slowly adding to my dirted tank in terms of hardscapes and now i'm deciding whether i should put a large rock in.

I am worried that it might compact the 1.5 inch dirt and 1.5 inch small gravel on top and cause anaerobic conditions underneath the rocks in a few months.

Any thoughts and suggestions would be greatly appreciated.
 

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Hi all.

I was wondering if anyone has experience having large rocks placed on top of their dirted tank setup.

I've been slowly adding to my dirted tank in terms of hardscapes and now i'm deciding whether i should put a large rock in.

I am worried that it might compact the 1.5 inch dirt and 1.5 inch small gravel on top and cause anaerobic conditions underneath the rocks in a few months.

Any thoughts and suggestions would be greatly appreciated.
I have an eggcrate diffuser at the bottom, then about 1/2-1" soil in certain areas and about 1" of blasting sand on top. My hardscape sits on top and I've had to 'burp' my substrate for the first few months by poking down with a wooden skewer. After the few months I've just let the plants root down and they mostly take care of any gasses underneath. Here's how my tank looks with the rocks over the dirted substrate.

 

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Discussion Starter · #3 ·
Thanks Econde, i was thinking about a shelf of some sort to relieve the pressure. Nice to know that it works for you. I might have to look into something like that.
 

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I have about 1" of soil and 1 1/2" of gravel cap and I have a couple of medium sized rocks on top of this. I would not do this now because of the risks of severely anaerobic pockets, but it hasn't caused any issues and the tank is almost 6 months old. Like @Econde I burped my substrate in the beginning, and I also have crypts planted around the edge of the rocks and I imagine their roots also help with aeration. I also did not throughly sift my soil, so there was some soil structure and variable particle sizes that probably also help with compaction.

I had read something before set up that led me to believe that the issue of anaerobic soil was overblown, but I think that was primarily aimed at people using a soil with low organic matter, which does not describe my substrate at all. It worked out, but it definitely would have been safer to have my hardscape supported or sitting on directly on the bottom of the tank. (Or my tank is a sitting time bomb that hasn't gone off yet, given the length of time and all the plant roots I doubt it.)
 

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Thanks Econde, i was thinking about a shelf of some sort to relieve the pressure. Nice to know that it works for you. I might have to look into something like that.
Not sure where you're from but I got mine from Lowes. Here it is!
 

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Discussion Starter · #6 ·
I have about 1" of soil and 1 1/2" of gravel cap and I have a couple of medium sized rocks on top of this. I would not do this now because of the risks of severely anaerobic pockets, but it hasn't caused any issues and the tank is almost 6 months old. Like @Econde I burped my substrate in the beginning, and I also have crypts planted around the edge of the rocks and I imagine their roots also help with aeration. I also did not throughly sift my soil, so there was some soil structure and variable particle sizes that probably also help with compaction.

I had read something before set up that led me to believe that the issue of anaerobic soil was overblown, but I think that was primarily aimed at people using a soil with low organic matter, which does not describe my substrate at all. It worked out, but it definitely would have been safer to have my hardscape supported or sitting on directly on the bottom of the tank. (Or my tank is a sitting time bomb that hasn't gone off yet, given the length of time and all the plant roots I doubt it.)
Thank you for sharing ElleDee. My feelings somewhat reflects your in that i am not certain that it will be an issue with what i got in my substrate. HOWEVER, the other part of me does not really want to risk it and having to start all over with my tank especially i don't have the fancy test kits to sniff out potential issues so i'm kinda torn ATM. Going to look for something like what Econde suggested.
 

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In all honesty it should stabilize after a while. My dirt was sifted thoroughly and it still had a lot of organic materials in there. I dont beleive you'll have to start over.

I would wait it out. But that's just me though.
 

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Discussion Starter · #8 ·
@Econde I did sift out my dirt also, there's definitely no large organic material. IF there were, it's like pepper grind sized. So in your opinion you think it'll be fine for me to just put the rock on top of my gravel without any support underneath? Just to be clear i'm not holding you to your opinion if things go awry, all responsibility will be on me since i'll be the one that's making the final decision :D I'm just really curious as to what people think and experienced, hence this thread :)

I've got two other 5 gallon tanks with dirt and gravel on top, no filter, no nothing, just light and heat. one's going on two years now and the other one a bit years now. The first one has no scape and is absolutely balanced, water's crystal clear, barely have to change it in months. Honestly i only really top off LOL. The second one has two small stones in it and it experiences some diatom blooms now and then but nothing crazy, i think's cuz of extra light TBH when my son forgets to close his blinds.

However, both of those smaller tanks does burp large gas bubbles now and then when the stand get's kicked by accident and that's what got me thinking.
 

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@Econde I did sift out my dirt also, there's definitely no large organic material. IF there were, it's like pepper grind sized. So in your opinion you think it'll be fine for me to just put the rock on top of my gravel without any support underneath? Just to be clear i'm not holding you to your opinion if things go awry, all responsibility will be on me since i'll be the one that's making the final decision :D I'm just really curious as to what people think and experienced, hence this thread :)

I've got two other 5 gallon tanks with dirt and gravel on top, no filter, no nothing, just light and heat. one's going on two years now and the other one a bit years now. The first one has no scape and is absolutely balanced, water's crystal clear, barely have to change it in months. Honestly i only really top off LOL. The second one has two small stones in it and it experiences some diatom blooms now and then but nothing crazy, i think's cuz of extra light TBH when my son forgets to close his blinds.

However, both of those smaller tanks does burp large gas bubbles now and then when the stand get's kicked by accident and that's what got me thinking.
Awesome. Yea I put the plastic eggcrate diffuser first, then dirt, capped it off with the fine version of black diamond blasting sand then put my hardscape over it. So even with the plastic diffuser at the bottom, my hardscape is essentially sitting over the capped dirt. Again I haven't had any major nor any minor issues really.

I do keep up with at least 1x 60-75% water change, sometimes twice a week now ever since I've hopped over the high tech side. Before that, still really had no issues with the walstad-ish, low tech. YMMV though. So good luck onto whatever you decide!
 

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No problem! Let us know how everything turns out for you.
 
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