# In praise of the true blackwater tank



## anastasisariel (Oct 4, 2009)

Funny I just setup a Blackwater tank yesterday. Not sure if it would meet your criteria for "true blackwater"
















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## Grah the great (Jul 3, 2013)

Looks like one! What's the water parameters? Tannins in general work against algae, but they won't compensate for significant KH and GH values that many softwater fish don't appreciate. For comparison...my 5 gallon licorice gourami tank has a TDS in the teens to low 20's ppm, PH in the low to mid 4's (4.4 last water change), and KH and GH both zero. Blackwater tanks are more stable if the PH and KH are deliberately made as low as possible (otherwise either the PH will be too high for most blackwater fish or it will be prone to spectacularly crashing at the fish's expense)


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## longgonedaddy (Dec 9, 2012)

There are a few of us members who have had blackwater tanks for some time. Have you checked our journals?


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## Grah the great (Jul 3, 2013)

longgonedaddy said:


> There are a few of us members who have had blackwater tanks for some time. Have you checked our journals?


I will have to do that! Thankx  What do you like about blackwater tanks?


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## longgonedaddy (Dec 9, 2012)

Grah the great said:


> I will have to do that! Thankx  What do you like about blackwater tanks?


Short answer, they're real. Like the difference between taking a walk through the woods, vs a botanical garden, the blackwater tank vs the manicured planted tank is a much more accurate depiction of nature. 

Long answer, read my journal, you'll see why. :wink2:


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## anastasisariel (Oct 4, 2009)

Grah the great said:


> Looks like one! What's the water parameters? Tannins in general work against algae, but they won't compensate for significant KH and GH values that many softwater fish don't appreciate. For comparison...my 5 gallon licorice gourami tank has a TDS in the teens to low 20's ppm, PH in the low to mid 4's (4.4 last water change), and KH and GH both zero. Blackwater tanks are more stable if the PH and KH are deliberately made as low as possible (otherwise either the PH will be too high for most blackwater fish or it will be prone to spectacularly crashing at the fish's expense)


Im only using tap so id guess 7.4 on PH. Its literally only on its 3rd day so I havent tested parameters yet. Im not really going to be agressive with dropping the PH. Im sure over time that monster DW will slowly drop it, but I guess I'll see. 

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## Grah the great (Jul 3, 2013)

Oh...almost forgot a BIG plus!
*No pest snails* - At a PH of about 6 pest snails have a way of persisting even if there is virtually no calcium in the water, but when it drops into the 4's (probably earlier) pest snail populations die within days. I'm not a hugely anti-snail person, but it's worth noting


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## longgonedaddy (Dec 9, 2012)

Grah the great said:


> Oh...almost forgot a BIG plus!
> *No a pest snails* - At a PH of about 6 pest snails have a way of persisting even if there is virtually no calcium in the water, but when it drops into the 4's (probably earlier) pest snail populations die within days. I'm not a hugely anti-snail person, but it's worth noting


I disagree. My snails' populations significantly increased from my planted tank, which had conditions much more favorable than my current blackwater tank.


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## GrampsGrunge (Jun 18, 2012)

Actually no algae isn't always true, our water from our well is close to being temperate rainforest blackwater, but it will grow diatoms like crazy with the least amount of additional ferts and light.

Google map image of a nearby lake bordering the Oregon Dunes Park, yeah, that's blackwater.


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## Grah the great (Jul 3, 2013)

Perhaps I should clarify some of the above...
*'No snails'* - Snails will persist into the high 5's PH (which is where my tank was before I started using sodium bisulfate). Dipping the PH in the 4's and keeping it there will kill the snails within a week at most.
*'Little/no algae'* - Strictly speaking, there's nothing preventing algae from growing in a blackwater tank. However, the low light levels, lack of nutrients, and copious CO2 (for the true plants present in the tank) means that, in my experience, algae doesn't thrive in blackwater tanks (I've never seen any except for a early tank that had a PH of 6 and was half tap, half rainwater...that tank had a mild case of greenspot algae. I haven't seen algae in my blackwater tanks since), and algae is not common in most blackwater habitats unless they're in direct sun


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