# Soil Substrate and PH



## rpadgett37 (Jan 2, 2014)

I am planning to set up my first planted aquarium using soil and a gravel cap. I'd like to know what impact, if any, the PH of the soil will have on the PH of the water.


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## lochaber (Jan 23, 2012)

I think most likely is that the organics in the soil will release tannins and humic compounds that will lower the pH somewhat. However, depending on the soil mix, if it has a lot of lime/carbonates, that might counter that, or even raise the pH some.


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## lauraleellbp (Feb 3, 2008)

lochaber said:


> I think most likely is that the organics in the soil will release tannins and humic compounds that will lower the pH somewhat. However, depending on the soil mix, if it has a lot of lime/carbonates, that might counter that, or even raise the pH some.


Agreed.

Also depends on how buffered your tap water is to start off with. 

Every tank could be a little different.

9x out of 10, I'd expect soil with a high organic content to lower your pH at least a little.


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## rpadgett37 (Jan 2, 2014)

Buffering the water won't be a problem. Sounds like it would be beneficial to run a test bottle before putting it in the aquarium.​Under what conditions would you need to add lime to the soil? What does it do for the soil and plants and how would it affect the ecology of the aquarium?


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## lochaber (Jan 23, 2012)

I wouldn't worry too much about it, and I think in general there is too much emphasis placed on pH. 

Unless you are trying to breed some pretty picky fish, most critters will probably do okay as long as the water is relatively stable.

Some of the guides for MTS and such recommend putting a bit of dolomite on the very bottom, I think it's to help keep the substrate from being too acidic, while providing some Mg and Ca.

It kinda depends on your water, if you have fairly hard water, you probably don't need to worry about it, as regular water changes will bring in a certain amount of minerals. If you water is pretty soft, you might want a bit.

Dirted tanks are a bit 'rough', and are hard to get to adhere to really precise parameters. At the same time, they can work really well for a lot of people, especially if you take a bit more 'hands-off' type approach. If you aren't set on a specific fish/plant combo, it would probably work best to just set up your tank, plant it with a bit of a variety, and do a fishless cycle. Once the cycle is complete, do a couple water tests, and then pick fish that work well in those ranges.


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## rpadgett37 (Jan 2, 2014)

lochaber said:


> I wouldn't worry too much about it, and I think in general there is too much emphasis placed on pH.
> 
> Unless you are trying to breed some pretty picky fish, most critters will probably do okay as long as the water is relatively stable.
> 
> ...


Nope. Nothing prickly. Just a Betta, some shrimp and a snail or two. And I'll look into the Dolomite.

As for the water, I am using RO water. For a dirt tank, do you reconstitute the water as you would in any other aquarium?


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## lauraleellbp (Feb 3, 2008)

If you're using RO water I'd reconstitute itt.


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## exv152 (Jun 8, 2009)

I shy away from using organic potting mix only because I do a lot of uprooting and it can cause a mess. Instead I use the commercially available soils like ada and stratum, has worked great.


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## rpadgett37 (Jan 2, 2014)

Thanks very much for the info. Given me some things to chew on.

Last question, for the soil cap, where on earth would I find a gravel that has a grain size of 2-3mm?


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## exv152 (Jun 8, 2009)

rpadgett37 said:


> Last question, for the soil cap, where on earth would I find a gravel that has a grain size of 2-3mm?


You're basically looking at coarse sand. You can use coarse play sand, or you can buy the more expensive aquarium stuff sold at the LFS under brands like carib sea etc.http://www.3reef.com/fish/sitepics/caribsea.jpg


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## lochaber (Jan 23, 2012)

I've never used RO water, just treated tap water. But if I were, I'd imagine I'd probably just cut it with treated tap water.

As for the cap, lots of people have had good results with both pool filter sand and coal slag blasting grit (I can never remember which grain size...), so those are two inexpensive options.


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## rpadgett37 (Jan 2, 2014)

Here's the potting soil I picked and the gravel cap. I'd say the size of the grains are between 3 and 5 mm. Would this be suitable. Got that before I knew about the coal slag stuff. Where would I find that?

Also, I am inclined to agree about the tap water.


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## rpadgett37 (Jan 2, 2014)

Gravel in the pic is too big afterall.

Would there be any issues if I capped the soil with flourite clay gravel. The grain size is perfect and the clay will greatly assist in controlling turbidity.

Is this a fundamentally flawed idea?


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## exv152 (Jun 8, 2009)

rpadgett37 said:


> Gravel in the pic is too big afterall.
> 
> Would there be any issues if I capped the soil with flourite clay gravel. The grain size is perfect and the clay will greatly assist in controlling turbidity.
> 
> Is this a fundamentally flawed idea?



Flourite will work, but if it's not rinsed well it can make the water just as cloudy if not worse. I would rinse it well and fill the tank really slowly with a gentle trickle of water onto a plate to not disturb the bottom.


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## lochaber (Jan 23, 2012)

My last tank was MGOCPM with a flourite gravel cap. worked great. I didn't sift the MGOCPM though, and after a couple months had a couple sticks/chunks make their way to the surface, didn't really bother me much though.

I didn't have cloudiness issues with the flourite (and I'm too lazy to rinse it) - I just put the substrate in, and then misted it with a spray bottle while planting, then gave it another fairly heavy misting before adding the water (poured onto a large filter sponge). I think the misting washed the fines down into the lower levels, so they didn't end up in the water column.

If you are using a gravel, you might need a slightly thicker cap layer then if you were using a sand.


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