killing algae, how to do it.

[Del Roach]

I want to get rid of green and black algae.  what's the best way.  Should I us algaecides?

 

[Jonathan Kadish NYC AA Chair]

The algae will always come back unless you cut off the light source.

[Jon Parr]

I agree with JK, fix the cause not the result. Where exactly is the algae, and why do you want to kill it?

[Carey Ma]

1 Cut light source as m,entioned above.

2 Mechanial extraction - physically remove with brish and seive.

3 Increase nitrifying bacteria by adding some and make your bio filter and/ or grow beds a comfortable habitat like increasing water temps.

4 Dip Barley straw

[WaterFish22]

Algae eating fish work nice for the green algae!

[Don Stark]

snails and other detrivores can and will eat your algae and then feed them to the tilapia... makes a nice snack

[Del Roach]

Thanks for your response.  I just lost all of my young tilapia.  To explain further, we noticed one large tilapia soon after adding them to the ft .  then we found about 3 floaters while the algae was getting more prolific.  after about two weeks we descovered all the fingerlings were gone completely.  We have now added a bag of barley to the ft and the algae is slowly going away.  We have now added 3 golf fish and they are doing well.  Thanks for any further help you may offer   Doc
 
Jon Parr said:

I agree with JK, fix the cause not the result. Where exactly is the algae, and why do you want to kill it?

[WaterFish22]

It seams like you had a spike in nutrients some how in the water, which caused the fish to die. The algae got more prolific because, it had the right conditions to grow (lots of nutrients in the water and lots of sunlight). If you have fish try testing your water more often and make sure its not overloaded with nutrients that are harmful for the fish. Your plants that your trying to grow will only use up so much of the nutrients, when then can't take any more in the algae will grow off of the rest.       

Del Roach said:

Thanks for your response.  I just lost all of my young tilapia.  To explain further, we noticed one large tilapia soon after adding them to the ft .  then we found about 3 floaters while the algae was getting more prolific.  after about two weeks we descovered all the fingerlings were gone completely.  We have now added a bag of barley to the ft and the algae is slowly going away.  We have now added 3 golf fish and they are doing well.  Thanks for any further help you may offer   Doc
 
Jon Parr said:

I agree with JK, fix the cause not the result. Where exactly is the algae, and why do you want to kill it?

[Chip Pilkington]

That is interesting, as Tilapia can live in green water quite well. Couple of things to consider...Something occured which caused the severe bloom and that needs investigation. Aside from that, the bloom wouldn't kill the fish if there is adequate DO. I don't know your system, but hopefully you are utilizing spray bars or airstones or something to increase DO. Aggitation from cascading water or spraybar really helps in my opinion. If you don't have those, initially, I would connect an airline to a "powerhead" style pump to create aggitation while introducing air until the conditions improve.

As many have nmentioned above, get rid of or at least reduce the light. I am also a big fan of large algae eaters (several varieties). They won't help an algae bloom (green water) but they work well to keep the sides and bottom clean.

[Jon Parr]

Right-O, Chip. The algae didn't kill the fish (at least not directly), and algae does a lot to absorb any possible nutrient spikes. Tilapia are freaking tough. I've had them survive water so putrid it would make you gag, with ammonia so strong it stings your nose. Not proud of that, but it's testimony to their strength. Low DO is likely the killer, but we really need more facts. What were your temps, pH, water chemistry, water turnover rates, stocking density, yada yada. How long we're the fish in before problems? How old is the system? Any recent changes? Any zinc, copper, or iron touching water, like a heating element? Anyway, barley should knock it down, but once the algae is gone you should yank the barley out. The barley straw should be well oxygenated, and it will produce lignen, and the lignen produces hydrogen peroxide when struck by sunlight. The H2O2 will kill the first single celled organism it contacts, usually free floating algae. The lignen itself is harmless throughout the system, but clear water will allow the H2O2 to survive long enough to damage the biofilter. Personally, I advise to fight the cause of algae, not the algae. Grow more plants, shade the water, employ algae eaters, etc. Good luck.

[WaterFish22]

Wanted to add this:

They also sell this chemical called aquashade. It turns the water blue so it blocks out the sunlight which slows down the algae growth. In my mine it's better then using an algaecides.  You can get it at any farm supply store. Another way that you can get rid of your algae problem is pump your water through a UV light. 

Jonathan Kadish said:

The algae will always come back unless you cut off the light source.

[matthew ferrell]

Big and sudden algae blooms do cause pH swings.  As they consume CO2 pH will rise, sometimes rapidly towards midday, and then drop at night.  This can be quite stressful even if O2 levels are stable.
 
Chip Pilkington said:

That is interesting, as Tilapia can live in green water quite well. Couple of things to consider...Something occured which caused the severe bloom and that needs investigation. Aside from that, the bloom wouldn't kill the fish if there is adequate DO. I don't know your system, but hopefully you are utilizing spray bars or airstones or something to increase DO. Aggitation from cascading water or spraybar really helps in my opinion. If you don't have those, initially, I would connect an airline to a "powerhead" style pump to create aggitation while introducing air until the conditions improve.

As many have nmentioned above, get rid of or at least reduce the light. I am also a big fan of large algae eaters (several varieties). They won't help an algae bloom (green water) but they work well to keep the sides and bottom clean.

[Chip Pilkington]

What kind of swings have you measured during a bloom?

Tilapia are pH tolerant as well...mine get some abrupt swings this time of year with our monsoon rains, as the rain water knocks down my normally high pH (7.8-8.0) to around 7, just in one quick storm due to super heavy rain. During a big squall, the temps drop quickly as well from the cool rain adding to the issue. I have yet to lose a fish - Tilapia can really tolerate a lot.

I'm still thinking it wasn't the bloom that killed those fish. That said, we really don't have enough information at this point to do more than speculate.