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Brown Algae(?) In Established Tank

6961 Views 8 Replies 7 Participants Last post by  willknowitall
I have a 25 gallon tank that has been up and running for about 2 years. Pressurized CO2 , 2 T5HO bulbs about 8 inches above the top of the water, moderately planted, EI dosing.

Ever since the tank has been set up, I've noticed that my plants get cruddy looking fairly quickly. When I add new plants to the tank, they grow very well, but they seem to become covered with a layer of what looks like brown "dust" within a week or two. Its not really dust as it is not easily removed from the leaves. New growth on fast growing plants appears to be fine and then, again, within a week or so, it is brown and cruddy looking. I'll also get patches of brown "dust" growing on the glass near the substrate (flourite) very frequently.

Since the only brown algae I'd read about was diatoms and those are supposed to be a new tank issue, I'd just assumed that plants becoming cruddy looking in short order was just inherent to planted tanks. This weekend though I had the thought that maybe this is not normal behavior and that I have ongoing diatom issues due to high silicates in my tap water. It's embarrassing that it took 2 years to have the thought, but here I am.

I got a hold of 2 silicate tests and, with a healthy dose of skepticism, I've interpreted the results to mean that I have anywhere from 10 to 25 mg/l of silicate in my tank and tap water. I'm somewhat confident in these results as they're the result of numerous tests with both kits, one of which contained a 6gm/l reference solution. I know none of this is fool proof, but it's a best guess.

So, the questions I'd like to answer before I start trying to figure out how to remove silicates without removing phosphates (and avoiding RO/DI):
1) Is this cruddiness just normal behavior?
2) If not, are there any other brown, dusty looking algae to blame?
3) If not, does anyone have any reference for what constitutes high silicate values for a freshwater tank?

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This is a case where otos or BN pleco will help.

A UV sterilizer will help too.
Got any rocks in there that you sourced out locally?
The hardscape is only flourite and store bought driftwood that I soaked and boiled. No rocks at all.

I've read that otos and plecos can help clean up, but I was hoping to get to the source of what is causing this.
A heavier planted tank might help too. Algae wants to happen. They live where plants live. There's no away around it.
I've just started getting a dark layer of brown algae on my plants as well, driving me crazy, i just put an otto cat in there to eat some of it hopefully. Maybe that will help you as well?
And i have stopped dosing nitrogen, and did another water change. My tank has also been set up for awhile.
i too have been cursed with brown dust on all the plants, new and old growth. But Ive jusr read the thread and noticed someone enquired about local stones etc. I have stones from my garden which I put in after rigourously cleaning. Could it be them?
EDIT: aparently its common in new tank setups, so that explains my problem. Id love to add some Otos but think that may overstock the tank :(
I'm also having the same problem. Mostly the brown algae is affecting my crypts bigger older leaves. The rest of my plants seem fine. Had bit on my glass too. Im hoping that it goes away on it's own, but Im thinking that as hard as it is to believe, perhaps I'm overfeeding. I'm going with heavy water changes for now. Will post any success
reduce light hours for three days, 4 hrs a day
bye bye
1 - 9 of 9 Posts
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