Getting red slime algae (cyano) when dosing Nitrates

[Bayinaung]

3+year old system. It's doing great. NO3 0, PO4 ~ 0.05 (hanna low range) for a very long time. When I started dosing nitrates (to increase it to 1-2ppm), within a day or 2 I would start to get red slime algae. I ignored the cyano, kept dosing, noticed that Acroporas grew faster within a week. However the red slime does get to be a bit too much where it started to grow on everything so I had to stop dosing. When it cleared, dosed just once, and it came back.

Are you guys getting red cyano when you dose nitrates and how did you deal with it to get that balance?

Thanks

 

[saltyfilmfolks]

How much (by vol) are you dosing?

Off hand , I’d say decrease the dose. The corals etc aren’t taking it up rapidly enough and it’s leaving leftovers for the cyano

 

[NY_Caveman]

I was dosing about 0.8 ppm per day into my 45 gallon tank when NO3 hit 0 ppm. I got the Cyanobacteria pretty bad same as you, but SPS were thriving. Tank is only 4 months old. Eventually I stopped dosing also as the Cyanobacteria spread. It is pretty easy to clear out, but it started going from a couple of spots to everywhere.

 

[Bayinaung]

How much (by vol) are you dosing?

Off hand , I’d say decrease the dose. The corals etc aren’t taking it up rapidly enough and it’s leaving leftovers for the cyano

I was dosing 0.5ppm/day 3-4 days in a row to bring it up. I start seeing red slime after 1st day, and usually a lot by 3rd or 4th day.

 

[Bayinaung]

Well that's the thing - I was able to bring my NO3 to 4-5ppm in my tank, and the acros had visible growth in 7 days! some had like 1/4 inch or more growth. But red slime got too much, I had to cut back. Acros are still doing great, but growth is much slower.

 

[Justfebreezeit]

What are you using to dose nitrate?

 

[Bayinaung]

What are you using to dose nitrate?

Flourish nitrogen. which is basically KNO3. I'm not dosing a lot as you can see.

 

[Randy Holmes-Farley Verified Community Expert]

Encouraging algae and cyano is the reason folks have not traditionally dosed nutrients, and is a risk. I agree that backing off the dose until the corals look good but the cyano thrives less is a fine approach, but may not work.

Shifting the balance to less cyano by manual removal or an antibiotic if the problem gets really bad may be appropriate.

What is the phosphate level?

Reducing organics may help as cyano may consume them (more skimming, GAC, Purigen, etc.).

 

[Randy Holmes-Farley Verified Community Expert]

Flourish nitrogen. which is basically KNO3. I'm not dosing a lot as you can see.

I don't know if it will help, but switching to a pure nitrate source from the mix of nitrogen compounds that Seachem uses may be useful. Food grade sodium or potassium nitrate, for example. I'm not a fan of the urea in Fluorish.

 

[Bayinaung]

Encouraging algae and cyano is the reason folks have not traditionally dosed nutrients, and is a risk. I agree that backing off the dose until the corals look good but the cyano thrives less is a fine approach, but may not work.

Shifting the balance to less cyano by manual removal or an antibiotic if the problem gets really bad may be appropriate.

What is the phosphate level?

Reducing organics may help as cyano may consume them (more skimming, GAC, Purigen, etc.).

Hi Randy thanks for responding to my post! my phosphate level is ~0.05 per hanna low range test. I have an over-sized skimmer (rated for 100/120 gals) for the 40 gallon (total volume) tank, and it skims about 1/2 of the cup every 2 weeks so the skimmer's doing its part. I will add more GAC.

 

[sghera64]

Been there and done that.

I went to a 3 day blackout and got rid of my cyano. But in my case, my NO3 went from zero to 16, to 20, then 24.

My theory is that cyano can be a NO3 sponge - - but it can respire simply on N2 as well. And our air is about 79% N2.

My cyano remains gone (5 weeks ago) but NO3 is still around 20. I stopped adding Ca(NO3)2 five weeks ago after the light out.

If you have a DSB it may also be sinking your NO3 additions and trick you into over adding NO3.

My advice is to stop NO3, rid the cyano (chemi-clean or 3-day blackout), measure NO3, then go slow.

 

[Bayinaung]

I don't know if it will help, but switching to a pure nitrate source from the mix of nitrogen compounds that Seachem uses may be useful. Food grade sodium or potassium nitrate, for example. I'm not a fan of the urea in Fluorish.

Good point, I didn't realize Seachem uses Urea. I thought it was simple KNO3. I'm going to get some food grade sodium nitrate. I know I have searched for it in Canada before and it was difficult to find.

If I use potassium nitrate, will it cause issues with elevated potassium levels?

 

[Randy Holmes-Farley Verified Community Expert]

Good point, I didn't realize Seachem uses Urea. I thought it was simple KNO3. I'm going to get some food grade sodium nitrate. I know I have searched for it in Canada before and it was difficult to find.

If I use potassium nitrate, will it cause issues with elevated potassium levels?

Probably not. Have you ever checked potassium?

 

[Bayinaung]

Been there and done that.

I went to a 3 day blackout and got rid of my cyano. But in my case, my NO3 went from zero to 16, to 20, then 24.

My theory is that cyano can be a NO3 sponge - - but it can respire simply on N2 as well. And our air is about 79% N2.

My cyano remains gone (5 weeks ago) but NO3 is still around 20. I stopped adding Ca(NO3)2 five weeks ago after the light out.

If you have a DSB it may also be sinking your NO3 additions and trick you into over adding NO3.

My advice is to stop NO3, rid the cyano (chemi-clean or 3-day blackout), measure NO3, then go slow.

I'm jealous. I wish I had to deal with 20 level nitrates! I wouldn't be concerned with nitrates at 20 unless there's algae or cyano. A friend of mine's tank is choking with acroporas and his nitrates are 30-40. And no algae, no cyano.

 

[Bayinaung]

Probably not. Have you ever checked potassium?

nope! never checked potassium. I simply assumed that regular water changes kept potassium at the level of the salt (Fritz pro). I had very little algae prior to dosing, used to have to clean the glass once a week. now it's every 4 days.

 

[Bayinaung]

Randy, what are your thoughts on Calcium Nitrate vs. potassium nitrate or sodium nitrate for reef use? Thanks!

 

[Randy Holmes-Farley Verified Community Expert]

nope! never checked potassium. I simply assumed that regular water changes kept potassium at the level of the salt (Fritz pro). .

It might. Mine never drifted up or down without dosing, and presumably regular water changes helped.

 

[Dan_P]

Hi Randy thanks for responding to my post! my phosphate level is ~0.05 per hanna low range test. I have an over-sized skimmer (rated for 100/120 gals) for the 40 gallon (total volume) tank, and it skims about 1/2 of the cup every 2 weeks so the skimmer's doing its part. I will add more GAC.

Skimmers remove more material per unit of time the more foam that is produced. 4 ounces of skimmate every two weeks is actually not skimming very much at all. Even 4 ounces of skimmate per day would not be skimming aggressively. If you think removing organics is important, consider increasing foam collection to the maximum that is practical for you, e.g., maybe you only have time to empty a full collection cup every two days.

 

[Dan_P]

It is pretty easy to clear out, but it started going from a couple of spots to everywhere.

I find this observation interesting. It might be the first time I read that someone said cyanobacteria was easy to clear out.

What were you dosing?

 

[KJAG]

I don't know if it will help, but switching to a pure nitrate source from the mix of nitrogen compounds that Seachem uses may be useful. Food grade sodium or potassium nitrate, for example. I'm not a fan of the urea in Fluorish.

Randy, what are your thoughts on Loudwolf Trisodium Phosphate and Sodium Nitrate? I was using Brightwell’s products for awhile but it’s just too expensive in my 200 gallon. What is the difference between products such as these and the food grade options? Thanks.