Fluval bio-stratum and a new tank

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Jul 19, 2022
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I'm wondering if the aqua soil is causing my cycling issues with my new tank... I've used some gravel, rocks and plants from my cycled tank. I also used filter media from the filter of another cycled tank... I am still doing daily water changes due to high nitrite. The nitrate levels are also around 25ppm to 50... I put a layer of fluval stratum under the sand for the plants.. Could that be the issue?.


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I cannot be definitive here, but I do recall a thread a few years ago that dealt with this same issue and the cause was put down to the substrate being Fluval Stratum. I just looked this up on the Fluval website, and I must say they do make some rather worrying claims. And maybe ammonia or nitrite, whichever, is a result.

  • Porous structure allows for rapid colonization of beneficial nitrifying bacteria
It may well, but why? The last thing you need in a planted tank is nitrifying bacteria to compete with the plants for the uptake of ammonia/ammonium. This bacteria will obviously appear, but encouraging it--no.
  • Encourages strong plant growth – roots easily penetrate and spread throughout substrate to obtain key nutrients
Maybe, but what nutrients specifically? They do not mention any that I can find.
  • Helps support neutral to slightly acidic pH – ideal for most plants, tropical fish and shrimp normally kept in planted aquariums
How exactly does it mess with the pH? Not something I would want occurring, for unknown reasons.
  • Will not discolor water and helps control organic discoloration when natural driftwood is present
Another unknown that could cause trouble for fish, depending how this achieves it. If it just contains carbon, not a problem in itself but carbon removes dissolved organics that are plant nutrients.
Damnit... I assumed the claims about ph were questionable... I did think twice about using it. However my friend has a tank with 75% of this stuff as substrate. His tank is basically carpeted with grass though.. I was trying to help out the plants and that's why I went with the stuff... I guess it can be taken out. It's only 10g.
Thanks guys,

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