# How do you build a "hill"



## xxxSHyXAxxx (Mar 16, 2011)

Kntry said:


> I'm going to use mineralized soil with black sand as a cap in my 75 gallon tank. I want to build up a hill on one side. Can I use cycled gravel to create the hill and then put dirt and sand on top?


the gravel may still erode over time. some people cut up light diffusers for florescent tube fixtures. I used small pieces of lava rock piled up and some strategically placed strips of corrugated plastic sheet. The biggest things is the ensure that it is not too dense because it may go anaerobic.


----------



## Bananableps (Nov 6, 2013)

Might want to consider making a false bottom with Styrofoam. I created a hill with just gravel held up by rocks. It shows no signs of eroding, but I'm constantly worried about the anaerobic activity that must be going on deep down in the 5" of gravel I piled up. A little anaerobic bacteria in your substrate is a good thing, but too much and can end up with serious problems.


----------



## Kntry (Dec 26, 2013)

Anaerobic build up was my concern. I wasn't too worried about erosion. 

Styrofoam is a great idea! It won't degrade or cause water pollution. Thank you!


----------



## OVT (Nov 29, 2011)

I personally use "egg crate" (plastic panels used to defuse light, ~$12 per 2' x 4'? at home depo) and lava rock. That combination helps to avoid dead substrate and provides extra surface for bacteria.

If you search for "egg crate" on this forum, you should find some how to do threads and some amazing tanks.

v3


----------



## Kntry (Dec 26, 2013)

I have bread crates that I use. They are much sturdier and free! I have pieces cut to fit the bottom of the tank so the rocks won't be sitting on the bottom.

If I stack pieces of crate up, the dirt is going to fall through the holes and still be thicker there, right? Should I put a piece of plastic over the crate to keep the dirt from filling in the holes?


----------



## OVT (Nov 29, 2011)

I would not use solid plastic as it would interfere with circulation in the substrate. I would just fill the crates up with small lava rocks you can buy at home depo < $10 a bag. Yes, some dirt would still make it to the bottom, but that's pretty much the case with any substrate, except very fine sand. So, no big deal - it will end up being your fertilizer. Eventually, your sand cap will start getting to the bottom also.

Planting some deep root plants in that area would also help to keep substrate healthy. Think crypts, swords, green temple, tiger lotus and such. You have a bigger tank that can accommodate them.

v3


----------



## 2pac (Jun 29, 2013)

lava boulders!


----------



## Kntry (Dec 26, 2013)

Ok, I'll fill the holes in the crate with lava "pebbles". That should work.

Thank you.


----------



## Bananableps (Nov 6, 2013)

Just to be clear, I would only recommend using polystyrene if you already had some lying around. That stuff is an environmental nightmare, and I would never tell anyone to buy new polystyrene if it could be at all avoided.

The egg crate is probably better, albeit elaborate. It gives your plants more room to grow roots, as well as increasing some of your in-tank biofiltration.

The one thing you really don't want to attempt with a false bottom is to create a space where water can accumulate and become still. I've read about paludariums that have gotten completely wrecked because some hollow false bottom started leaking and became filled with uncycled water.


----------



## Kntry (Dec 26, 2013)

Should I only use the crate under the rocks to keep them off the glass and not on the entire tank bottom?

I have lots of rocks and pieces of slate around my house. Would these work to build the hill?


----------



## Bananableps (Nov 6, 2013)

Do you ever plan on moving this aquarium?


----------



## Kntry (Dec 26, 2013)

No. It has been in the same place for 4 years, since we moved into the house.


----------



## OVT (Nov 29, 2011)

OVT said:


> If you search for "egg crate" on this forum, you should find some how to do threads and some amazing tanks.


You have asked for advise and I gave the best I had. This has been done before, many times, successfully. You can certainly experiment and see what works for you and what does not.

v3


----------



## Kntry (Dec 26, 2013)

Thank you. I really appreciate the help.

I'm also doing searches here tonight.


----------



## Kntry (Dec 26, 2013)

I've looked at every thread I could find on building up substrate.

I'm going to try cutting pieces of egg crate to build up the height and shape. I saw that people used waterfall foam or Great Stuff to build hills also but what I'm going to try is filling the egg crate with foam to keep the dirt out. 

Thank you so much for the help.


----------



## puopg (Sep 16, 2012)

I know in some videos I've seen like the making of Natures Chaos by James Findley, he uses substrate supports which are just flexible sheets of plastic or something. Maybe give those a look.


----------



## DaveFish (Oct 7, 2011)

Yeah I would use lava rubble. Has anyone ever heard of someone's fish dying or experiencing a sulfur bomb from hydrogen sulfide? I read that as the gas touches the water it becomes hydrosulfuric acid which isn't very caustic. Nothing like sulfuric acid. With lava rubble and plant roots I am sure you will be fine. I have honestly never heard of anyone actually getting a sulfur bomb tank that killed all their fish.


----------



## Kntry (Dec 26, 2013)

I have heard of this happening many times in ponds when people put rocks in the bottom. The rocks stay there for years collecting detritus. When they move sections of rock, the gas is released and kills the fish. 

So are you saying that the lava rubble would be better than Great Foam?


----------



## philipraposo1982 (Mar 6, 2014)

Why not just use large rocks to avoid piles of substrate?

Sent from my SGH-I747M using Tapatalk


----------



## rtl402 (Sep 23, 2007)

Depending on how large of a hill you are looking for you could just pile on the substrate.. I am setting up a 75g myself, with the left side (maybe 12" width) being elevated about 5" higher then the rest of the tank. I am going to pile up some rock and topsoil.. with a thin layer of black sand on top. Rest of the tank substrate is going to be black flourite sand at 2" thick


----------

