# Best substrate for SE Asia biotope



## Granberry (Mar 9, 2012)

I hesitate to use the term "biotope" because perhaps that implies something more complex than I'm doing, but please forgive if that's the wrong term. 

I am setting up a tank just for Celestial Pearl Danios, and I'm trying to replicate as best I can the SE Asia blackwater pool conditions. The plants I ordered today are red and green cryptocoryne, giant hairgrass, water sprite (Ceratopteris thalictroides) and I'm planning on picking up dwarf hairgrass too. 

My question is what type of substrate is best for this type of tank all things considered, i.e., plant needs, authentic appearance, etc. 

I am trying out a sponge filter to avoid high current, if that is significant. 

Also, I know some substrates can affect water hardness. Our water was hard (GH 17) but we have a Culligan water softener now, so it's softer, though I don't know the exact parameters.

I really appreciate this forum, and any any opinions, links to informational articles, etc. will be both welcomed and studied!


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## redchigh (Jan 20, 2010)

I'm a fan of black estes 'ultra reef' sand. It's cheap, totally inert (safe for freshwater) and blends well. Gives the appearence of sand, but is large enough to not compact. Also safe for loaches, which are also south american.


The problem, is that celestial pearl danios don't LIKE blackwater conditions. they prefer hard water with a high ph.

Which do you want? Blackwater biotope (perfect for rasboras, loaches, and gourami) or celestial pearl danios? 
You could compromise with a ph close to 7.0, but compromise isn't good for fish. Much better to get as close to ideal as possible. The substrate is fine for celestial pearl danios if you go with them, just use water from an outside spigot (that hopefully won't be going through the softener)


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## Granberry (Mar 9, 2012)

redchigh said:


> I'm a fan of black estes 'ultra reef' sand. It's cheap, totally inert (safe for freshwater) and blends well. Gives the appearence of sand, but is large enough to not compact. Also safe for loaches, which are also south american.
> 
> 
> The problem, is that celestial pearl danios don't LIKE blackwater conditions. they prefer hard water with a high ph.
> ...


I appreciate the suggestion so much, and I will definitely investigate it!

I read this on the tropical fish profiles tab above: "Soft (hardness below 5 dGH) slightly basic (pH 6.5-7.5) water, temperature 20-26C/68-79F. The water in its habit is slightly basic (alkaline) with a pH of 7.3 but is very soft."

So that's why I thought they needed soft water...I am not as well read as some, so if there's a conflict in information, I won't know it! I pretty much only know what I read here.


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## Byron (Mar 7, 2009)

That data is correct [I wrote it, so it was well researched]. The ideal water would be soft, with a pH around 7 (slightly acidic to slightly basic). As the CPD will be in a small tank, it will not be difficult to provide suitable water. On that, let's start with your tap water.

Do you know how the softener works? Some remove mineral salts (calcium, magnesium, etc which are what make water hard) by adding sodium salt (common "salt") and this is just as bad for these fish if not even worse.

Diluting the tap water (before it goes through the softener) with "pure" water like RO, distilled or rainwater would be best. Whatever the tank size, I would suggest half and half; this will reduce the GH which you say is 17 dGH by half, to 7-8 dGH, which is fine. The pH that results may be OK.

The tank needs to be well planted, and the plant species mentioned are fine. Also, lots of bits of driftwood, the Malaysian Driftwood available in many pet stores is ideal. You could also collect some dried leaves, oak and beech work fine, or you can buy almond leaves in some fish stores for this purpose. Not essential, but if you have the leaves they will work to soften and acidify too, as will the wood.

Byron.


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## Granberry (Mar 9, 2012)

I know our water softener (from Culligan) does not add salt to the water, but it certainly does remove those mineral salts you mentioned. It has 2 tanks. One contains a media (in the form of beads) that attracts the minerals in the water which adhere to the media. The second tank contains a brine solution that is used to flush those mineral deposits off the media periodically during a "backwash cycle", and then that brine water goes out the drain, and not back into the water supply. The website explanation says, "Water softners do not ever add salt to your water system unless they become defective and plug up somewhere during the backwash cycle." However, it does remove calcium and other minerals, and for that reason, I know I can't have aquatic snails (their shells would be too soft). I will definitely double check all this as well as test the water, but actually I might use the outside spigot regardless and add half rainwater as you suggested. I like the idea of adding rainwater and almond leaves to organically soften the water. 

I'll check the pH before I add water to the tank too (it is 24 x 11 x 11). 

I looked at your picture of your Asian stream lagoon, and it was beautiful! I had never seen fish like the ones you had in there. They are just as gorgeous as the CPD. 

As always, thanks for taking the time to add your expert opinion!


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## Byron (Mar 7, 2009)

The water softener sounds good. I would simply take half softened water and half non-softened, or roughly, to get the desired water. Rainwater would also have the effect of lower pH, do depending upon what the pH is, that's an option with or without.

On the snails, Malaysian Livebearing snails are ideal for planted tanks, they burrow throughout the substrate, and they will thrive in any water, soft or hard. My near-zero hardness doesn't stop these snails, I have hundreds.

I forgot to comment on substrate previously, got carried away with water. As noted in our profile, the substrate should be dark to calm the fish and bring out its best colouration. Fine black sand or gravel would work, though I am more fond of a more mixed substrate, something like playsand. Being really authentic, a dark brown substrate representing the muddy natural habitat, with leaf cover.


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## redchigh (Jan 20, 2010)

Wow, I'm not even sure where I read that they preferred hard water... Maybe I just assumed it because they're native to mountainous regions. Thanks for correcting me, Byron. I might decide to get some CPD's after all, for my 20G long...


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## Granberry (Mar 9, 2012)

*Final product*

I thought I'd let you see how the final product turned out, though I guess things are never fully final! 

This is a 13.5-gallon, 24 x 11 x 11, tank with black sand substrate. The log is resin, and the plants are dwarf hairgrass, giant hairgrass, and red and green wendtii. I let water lettuce float for now, though I don't know if I'll keep it. The water is already soft, so I don't know if I'll add driftwood or leaves, but I'll figure that out as I go along.

The light I'm using right now is a T5 set up, but I am going to change that. Also, the filter is still on it's way from Amazon, and it's a hydro II sponge filter. I am hoping it won't create much of a current.

The only fish I'm going to keep in this tank are Celestial Pearl Danios. I had ordered 10, but a day passed between when they finished quarantine at the fish store and the day I went in to pick them up, and in that day, somebody bought all of them. Grrr. Oh well, I have my name on another list somewhere. 

Anyway, thanks for everyone's help!


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## Byron (Mar 7, 2009)

Looking good indeed. :-D

The Hydro are good filters, i have one. It will be fine, down behind the "log" out of sight more or less.


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