Blue green algae?

[mell]

Hi all, to those of you who have battled blue green algae in the past, can you tell me if this is similar to what you've seen? I'm 90% sure that's what it is- lighting doesn't seem to affect it and it grows through if I cap it with sand, and it has a putrid smell. It's dark green and slimy, and if left long enough forms a thick skin across everything. I've tried spot treating it with hydrogen peroxide 3% at 2mL per gallon with little to no effect, whereas others have said this method has worked wonders for them and you can literally watch the algae turn brown and detach- which leaves me a little unsure of whether it actually is blue green algae?

I let it grow for a while to get a good representation. You can see in the photo that if thick enough the 'skin' just peels right away.



The only other algae in my tank is green hair algae. I have 2WPG t5 lighting which is on for 8 hours a day. An air stone comes on when the lights are off. I use Flourish once a week after 40% water changes, but I've stopped dosing to see if it made any difference, and it didn't seem to. I have no added co2 and I don't dose macro nutrients. I'd say the tank is moderately planted.

What do you guys think it is/is causing it? Has anyone tried fighting BGA with Maracyn?

 

[octavusprime]

Definately blue green algae, although it really isn't algae but a cyanobacteria. This bacteria thrives in low oxygen environments. How strong is the current in your tank? You should have some surface agitation (small ripples on the surface) to promote gas exchange. In addition there should be adequet flow in the tank to ensure this oxygenated water circulates to all areas of the tank. It is not uncommon for areas of a tank to have "dead" spots but you should work to minimize this. Try manipulating your filter output to increase surface agitation and if needed add a powerhead/fan to create a current in the tank. You don't need much current but your plants should wave slightly. Turning your lights off for 3 days and cleaning out the tank can help lower the cyano bacteria population but you must get to the heart of the problem: lack of proper fertilization.

I would consider adding trace minerals and Potassium at a bear minimum. Your fish will produce Nitrate and the fish food provides phosphorus but probably not enough to support the amount of light in your tank. The plants will only grow if they have all nutrients they need. If they are lacking say potassium they will stop growing and thus stop taking up nitrate and phosphorus. This in turn provides nutrients for the cyano bacteria. The excel is a source of Carbon but for healthy plants you will need to provide adequet Nitrates, Phosphorus, Potassium and micronutrients as well.

T5 lights are great but its like having a supercharged engine and not providing oil to the car. I would highly recommend going to the EI method of fertilization or similar. http://www.barrreport.com/showthread.php/2819-EI-light-for-those-less-techy-folks If you don't fertilize correctly you will continue to have algae blooms and your plants and fish will suffer.

Hope this helps. Keep at it a balance can be found and a healthy tank will be had.

 

[mell]

I'll definitely work on increasing water movement, thanks for the tip. At the moment it's not too strong because of the angels but surface agitation can definitely be improved at least. I'm still getting grips on the lighting-CO2-nutrients balance. I dose with the original Flourish so that hopefully covers the micronutrients and I'll look for a potassium additive the next time I'm out. I also don't use flake foods and rarely use pellets so there could be an issue with phosphorus as well. eep so many flaws in my system. Definitely helpful, thanks for the info and the link, I'll have a look in the morning!