Can't get rid of blue-green slime algae

[falcon]

I have a 65g with 192wpg pc light 6700k. Pressurized co2, kh5, gh3, ph 6.5. The tank has been running for 7 months now. Initially, the growth was good and no algae at all. But for the last three or four months, I am battling this slimy algae. I've read somewhere that this indicates poor water condition. In the tank, I have 10 medium altums, 4 h.raboras, 2 medium clown loaches, two medium albino plecos, and 5 corries. I change 50% of water once a week.

The growth has been non existent the last two months. But the last 2-3 weeks has started growing. The broblem, the algea, keeps covering the new growth in slime, detering plant growth.

For ferts, I am dosing 10ml of trace(PMDD recipe)x3days, 2mg of KNO3 x3days, and 5 drops of enemax3days. Recently, I started adding exel@5ml/day and 10ml@w/c.

Just can't get rid of it. For plants, I have mostly vals, some bacopa, and one other type. Recently, I have added a small ruben sword and 2 weeks later a small amazon sword to get some plant mass. I have put in root tabs in the substrate for those(one each). For substrate, I have 1 bag of fluorite to 4 bags of BA gravel. I am running rena xp3 on the tank.

Guys, any help or suggestions would be really appreciated as I am getting tired of this algae.

 

[happychem]

2 things that I think are wrong with your post - correct me if I'm wrong:
192wpg, do you perhaps mean 1.9wpg or do you have 12480 watts of PC over your tank?
2mg of KNO3, do you mean 2g? If not, then there's your problem.

The easiest way to deal with a serious BGA problem is to remove as much as you can, do a 50% water change, dose KNO3 to 10-15ppm and blackout for 4 days. After the blackout, do another 50% water change, dose KNO3, half as much as the initial, you're just replacing the water change.

Keep your NO3 levels between 10-15ppm and you should have no problems. BGA is an nitrogen-fixing photosynthetic bacteria, so it generally thrives when all other nutrients are fine but N is absent/limited. This means that plants and other algae strains will struggle to grow but since BGA can take N from dissolved N2, of which there is plenty, it grows. Blackouts work wonders at killing off existing cells, but you need to be attentive to keeping NO3 levels decent, otherwise it will return. I have a heck of a time keeping it out of my 18g tank, but mainly because I was trying to run it "low tech" with little to no dosing, I guess that didn't work .

 

[falcon]

Thanks, Happychem...

Ooops, I have around 3wpg(192w) and I dose 2g on KNO3.

I have tried the blackout but didn't really work. It subsided BGA, but it returned. I have been playing with nutrients lately and have been reducing KNO3 from the 2g that I dose thinking that my high fish load is supplying most of it. I guess not...Yesterday, I have returned to my previous dosing and will keep it up. Through the few months of fighting BGA, I have been increasing my co2 steadily. Not sure of the reading as my probe says 6.1, pH pen 6.5, and the liquid test around 6.5. I have been observing fish and plants, and plants are pearling good under BGA and on top as well. So, I think my co2 levels are good. Will keep up with nutrients. I mean that's what I have been doing going two months into BGA and then I started increasing co2 and playing with nutrients. I was out of ideas at that point...

Will stick with the schedule. In fact, I will increase KNO3 dosage to 2.5gx3days a week. What do you think? I might give the blackout another try over the weekend.

 

[happychem]

Hehe, I figured that they were typos, but I wanted to double check and get the real values for certain.

If I did my calculations correctly, each 2g addition is adding about 5ppm of NO3 to your water. If you dose this much all the time, you may be a little short. Try dosing about 5g after your water change and then dosing 2g every other day, along with PO4. Dose your traces on alternating days. This should maintain your NO3 level between 10-15ppm.

Trust the pH from the liquid indicator as your 'true' pH, I like my pH pen, but I don't trust it entirely, only if the number it reads makes sense, if it reports something I don't expect, I always double check with the liquid test. The liquid test is just straightforward acid-base chemistry with a little spectrochem thrown in, the electrochem of the pH pen is sensitive to so many things, the way you care for it, for example.

 

[falcon]

Thanks, Happychem...

Now, it makes more sense going in the other direction with ferts. Will try that for few weeks and see what happens. Maybe there is light at the end of the tunnel?

 

[happychem]

BGA is probably one of my least favourite types of algae, probably just because it's so unpleasant and you can't physically remove it as easily as, say, hair algae which just takes something to coil it around and yank. You'll get it, it just takes persistance.