Cyanobacteria - KNO3 - The Planted Tank Forum
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post #1 of 4 (permalink) Old 07-04-2012, 12:33 AM Thread Starter
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Join Date: May 2011
Location: USA
Posts: 39
Cyanobacteria - KNO3

I have an 18 gallon tank with no CO2 and one T5 bulb. I only have three or four stems in there with some amanos, crs, and tetras.

I've been reading up on my latest tank problem and apparently I need to keep some KNO3 on hand. My nitrates test low (5.0) and is probably the cause of cyanobacteria. I read the sticky and it's undergoing a black out right now.

My questions is how much and what quantity should I invest in some KNO3 and where is the best place to find it? My LFS told me to try a place that sells pond stuff... I think I rather just order it online.

They also told me to take out my plants. Should I?

Advice appreciated.
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post #2 of 4 (permalink) Old 07-04-2012, 12:43 AM
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Join Date: Oct 2011
Location: Dallas, TX
Posts: 997 is a good place. or green leaf aquariums. or nilocg on the power sellers forum. should be pretty cheap. probably less than 10$ shipped for a lb, which will last a while. there's a sticky in the fertilizers section that should help you out with dosing. the petaphile fert calculator is also quite handy, since it has a low tech option.

And, you don't need to take out your plants, and instead of doing a black out, i'd see if you have any erythromycin. It's very effective in taking care of the stuff without causing harm to your plants. It'll take less than a week to completely rid yourself of the stuff. you can sometimes get it over the counter at a pharmacy, which is much cheaper than the lfs.

Last edited by aweeby; 07-04-2012 at 12:43 AM. Reason: .
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post #3 of 4 (permalink) Old 07-04-2012, 02:12 AM
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Location: Houston, TX
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Cyanobacteria is often caused by low oxygen levels and high organics in the tank. A blackout is not a good idea.

Remove as much as you physically can. Perform a 50% (or more) water change. Increase filtration, including surface agitation. Continue to perform water changes every 1-2 days. As long as you have corrected the initial cause, it is possible this will clear it up.

If not, then you can try to kill it using H2O2. Be sure to remove any dead cyanobacteria from the tank so it doesn't increase the ammonia in the tank.

Then, if all that fails, try erythromycin (such as the fish med Maracyn).

Read this page to understand why oxygen is an important element in cyanobacteria:

Vicki Rena Filstar pimp #142 (four XP4s/three XP2s/one XP1) Eheim pimp #301 (Pro II 2128) Victor pimp #27 (VTS-253B-320)

90g - Journal Pelvicachromis taeniatus 'Moliwe' 75g - Journal Pelvicachromis pulcher 'Lagos Red' Better Pics 8-24
29g - Journal Pelvicachromis pulcher 'unknown' -- 29g - Pelvicachromis taeniatus 'Moliwe'
5g - RCS colony 2.5g - Journal Retired
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post #4 of 4 (permalink) Old 07-04-2012, 04:19 PM Thread Starter
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Posts: 39
Thanks fellows. I appreciate the help!
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