# Soil substrate in brackish tank?



## AlbaAquarist (6 Feb 2017)

I'm wasn't sure which sub-forum to post this, so apologies if I should have asked somewhere else.

Anyway I'm in the early planning stages of a low-end brackish (below 1.005) planted tank that will house a Figure Eight Puffer. My question is whether there would any reason not to use a soil substrate underneath Aragonite sand in this setup?


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## Andrew Butler (25 Feb 2017)

you get any answers anywhere?


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## three-fingers (25 Feb 2017)

Soil contains lots of nutrients, brackish water plants tend to be slower growing species like Java fern/moss and _Anubias _spp. so it could be a recipe for algae.

If you start with a high plant mass of faster growers like_ Sagittaria subulata_ or _Vallis_ spp. then it would be great, however in my experience these plants melt before adapting to brackish water, so you are almost certainly going to see lots of algae make use of the nutrients first.

I would just use sand and root tabs/clay fertiliser balls, unless you don't mind big algae blooms at the start.


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## AlbaAquarist (25 Feb 2017)

Andrew Butler said:


> you get any answers anywhere?



I have read mentions of soil/fertile substrates under sand for planted brackish aquariums, but not an awful lot of detail I'm afraid.



three-fingers said:


> Soil contains lots of nutrients, brackish water plants tend to be slower growing species like Java fern/moss and _Anubias _spp. so it could be a recipe for algae.
> 
> If you start with a high plant mass of faster growers like_ Sagittaria subulata_ or _Vallis_ spp. then it would be great, however in my experience these plants melt before adapting to brackish water, so you are almost certainly going to see lots of algae make use of the nutrients first.



Interesting, did you try any other plants? Also roughly what specific gravity was your tank at? There isn't a lot of information on planted brackish aquariums, at least compared to fresh, so it would be great to read about your experiences.

As for the slow growth, my plant list is primarily based around infomation from Iliveinazoo's in "Brackish Experiment" and his posts on a Puffer forum, as well other tidbits of information from various sites. I would definitely be planting heavily with most of the plants on his list and a few extra additions; also I would be utilising floating Ceratopteris thalictroides as my 'nutrient sponge'.

I believe the soil i'm planning to use is quite lean as well (velda pond soil) at least in comparison to mixes such as John Innes. However I was primarily worried that there may be reasons unknown to me that you shouldn't use soil with water of a brackish salinity, maybe I worry too much .


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## three-fingers (26 Feb 2017)

Only tried and Java fern and _Vallisnaeria_ as far as I remember, it was about 1.005 I think, a temporary display tank for mudskippers and molly fry, wasn't set up for long though, the vallis grew well.

_C.thalictroides_ would be great as a floating plant, never tried it in brackish myself.

No specific reason you shouldn't use soil, other than the fact avoiding algae blooms with low-tech soil substrate tanks is hard unless you start with enough healthy plants, and any plants added to brackish water will take a while to adapt. So worst case scenario, you have greenwater/algae on all the surfaces for a while to start with. Easy enough to fix, and it will be great for the plants long-term.

Good luck with your brackish planted tank! As you say, not much info on them around so they can be very interesting.


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## AlbaAquarist (27 Feb 2017)

three-fingers said:


> No specific reason you shouldn't use soil, other than the fact avoiding algae blooms with low-tech soil substrate tanks is hard unless you start with enough healthy plants, and any plants added to brackish water will take a while to adapt.



Great, thanks for the help. My plan is to let the plants settle in and adapt to submerged growth in hard fresh water, then after a couple of weeks gradually raise the salinity during each water-change up to around 1.003. The low salinity and slow increase will hopefully help the plants and limit algae as a result.


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