45g of Blue Green Algae, What else do I do?

[Addictedtobettas]

I've been fighting a recurring bloom of BGA in the 45g (and only the 45) and I'm at a loss as to next steps.

I lowered the lighting.
I switched from a higher nitrate fert to a lower one (thrive back to flourish) because nitrates are not dropping.
Plants are dying.
I now do larger water changes, to lower nitrates and phosphates.
I checked phosphates in tap water, .25 or lower compared to .5 to .75 in tank typically.
I added clearmax to remove phosphates.
Lowered the lighting again. Intensity and duration. Again.
I've tried to keep the flow decent but I can only do so much with an angelfish in there and little plant life compared to previously.

I lost one of my angelfish in that tank (don't think it was related, she was eggbound), and I'm not sure if some of the treatments I was doing for her aggravated the BGA but the aquarium salt seemed to help her and decrease the BGA but some of the plants were not thrilled with that.

I was going to add another UV filter (I have a dinky one in there now) and add a 2nd filtration unit (I have a fluval 407 and was going to upgrade with an fx4 I have), but then I'm not sure if that will do anything.
I was also thinking of adding a BUNCH of plants to replace the lost ones, absorb the nitrates and hopefully take the nutrients the BGA is getting now.

But then I started to wonder if I even should. Will that just 'infect' the new filters with BGA?

Typical numbers lately:
PH 7.2
Nitrites 0
Ammonia 0
Nitrates 30-40 no matter what I do now
Phosphates .75
Temp 79
Lights 6 hours a day at 50%

Anyone had success at beating it? The fish overall seem fine..

 

[FinalFins]

Have you tried a complete blackout yet?

 

[Addictedtobettas]

Have you tried a complete blackout yet?

Not really. I tried it for other algae and didn't have success, some time last year, it just left my plants faltering for the most part. I'd also read that for BGA it didn't really help but.. I guess at this point there isn't a long list of other options.

It seemed to have gotten better (as in somewhat less of it), so I added in thrive again last week. Pulled the lid off today to a huge section of Salvinia and other floaters just surrounded by it - directly under the lights of course, where I don't see much.

That smell!!