Blue Green Algae Problems

[amf17]

Tank Paramters
20 Gallon
GH 220ppm
KH 100ppm
Ph - 6.9
CO2 - 20ppm
Nitrate - 5ppm
Nitrite - 0ppm
Ammonia - 0ppm

I recently changed the lighting in my tank because my plants weren't growing very well and i figured the lighting was the problem. I changed the regular hood light to a 23 watt 6500K, 1600 lumen compact fluorescent (equivilant to a 100W incandescent).

I have had an outbreak of blue green algae and i don't know what I need to do to fix it. My tank parameters seem fine(posted above). I use seachem equilibrium to bring up my GH because my tap water has 0ppm GH. I don't fertilize regularly because the seachem equilibrium contains all the trace elements that plants need. I'm worried that if i add a fertilizer to the mix, the algae could get worse.


Any thoughts on what i might be doing wrong???

 

[Wolfenrook]

I can immediately see that your nitrate levels are way too low for plant growth, ideally you need them at above 20ppm, odds are your phosphate levels are as bad. With the extra lighting you have added your plants are needing even more nutrients, and as things stand they aren't getting these. So along comes our old friend BGA, not so needy for the old nutrients, but lurves your new lighting.

So 3 steps you should be thinking of taking now, step 1) make sure your water changes are nice and regular, 25% once a week does the job very nicely, 2) Check your circulation, make sure that water is circulating to all parts of the aquarium with no dead spots, 3) Start dosing a good fertiliser, and looking at your nitrate levels it needs to be one with macro nutrients in it, which means either using dry ferts or good old Tropica Plant Nutrition + (if this isn't available where you are, then Seachem do seperate N, P and K ferts, which you would need to use alongside normal Flourish).

You might also find that giving the plants a source of carbon helps, either via a product like Seachem Flourish Excel/EasyLife EasyCarbo or via the addition of CO2 via yeast based fermentation or pressurised kit (don't go higher than about 35ppm though, best way to monitor this is with a drop checker/permanent CO2 test containing the reagent and some pure water that has been buffered to 4dKH, AquaEssentials sell this ready made if you live in europe).

Ade

 

[Rob.S]

I'm worried that if i add a fertilizer to the mix, the algae could get worse.

I think it is generally accepted (by plant growers) that high NitrAte, and Phosphate levels are not the cause of BGA. I very much agree with Ade's post, but would add that if you start dosing ferts, then maybe you should do 50% weekly water changes.

You will need to kill off the BGA before going down the feeding & Co2 road, so............

Do a water change & remove as much BGA as possible. Switch off lighting, TOTALLY cover the tank with bin liners/blankets/whatever, to get a total blackout. Keep this for 3 days. No cheating! After 3 days, another 50% water change. Remember, this will kill off what is in the tank, but unless you can address the root of the problem, it will be back.

Good luck

 

[amf17]

Can you give me an approximate dosing schedule that i should follow when using Nutrafin NPK and Nutrafin trace using my above parameters???

The nutrafin NPK bottle says to add 5mL to ten gallons to get 3.5ppm Nitrate, .5ppm Phosphate, 2.5ppm Potassium

I'm just wondering how much i should add at one time and when i need to redose???