Can't ditch this BGA

Maybe this will subside on it's own with time, but I am having a problem with Blue-Green Algae growth in my tank. It is only in one spot in the center of the tank and it is only growing on the Java Moss. When I do my weekly water changes I vacuum it all off, but by midweek it's back again. It's destroying the moss.

The only thing that I can attribute to this was lean macro conditions when the tank was setup NPK(5-0.5-15) this was about 2 months ago though when I first started the tank. In my experience this type of algae goes away on it's own at 10ppm NO3 and good plant growth, but this is not the case here, which is why I am puzzled.

Here's an overall pic of the tank- although the plants have grown in a lot more now.


Here are the tank parameters:

Size= 4'x2'x2' 125g
Plant mass= moderate to heavy
Bio load= 4 adult Discus, 20 small schoolers, few other small fish
Feeding schedule= 4x's a day live and frozen food.

PH=6.55
kh=4*
gh=7*
c02=34ppm
Nitrate=10ppm
Phosphate=2ppm
Potassium= 12-18ppm

I do weekly 50% water changes and dose the following:
1.5tsp Potassium Nitrate
1.5tsp Potassium Sulfate
4ml Fleet enema


Then in addition I add twice a week:
1/4tsp Potassium Nitrate
.5 ml Fleet enema

Traces are added on days that I don't do macros a weekly total of 25ml Flourish and 30ml Flourish Iron.

Anyone have any suggestions on how to rid this tank of this pesty BGA before it really gets out of control?

Thanks!

 

Re: Can't ditch this BGA

Thanks for the response!

Hmmm. That's gonna be alot of meds on a 125g. I'm concerned with medicating the fish in the tank. I have $100's of fish in there so I'm very conservative with the use of any treatment. Maybe I should manually remove and try a blackout first? I just don't know why it is growing so well at these nutrient levels. Very frustrating especially because I've seen these nutrient levels decimate this stuff in the past.

 

Re: Can't ditch this BGA

Thanks for chiming in Tom. Had a feeling you'd say blackout and I think I'll give it a go first since this is less intrusive. Now If I'm doing this correctly I will continue to run the C02 and ferts as normal right? I'm a little concerned though about the dissolved oxygen levels during this time- the levels getting too low. Do you find that there is a need to run air bubbles during the blackout period?

Your friend has quite a setup by the sound of it. Like your friend I reduced the macros anticipating the addition of the Discus would give quite a bit of them, but apparently not enough with the Bio load and that probably is what got this whole thing started.

O yeah. I have an 18W UV plumbed in too that can be utilized. In your experience would running this 24/7 help my situation? I currently only use it rarely since I'm afraid it will take traces out of the water, but if you think it's OK maybe I'll just leave it on. Maybe this is for a new thread?


Thanks again

Jeff

 

Re: Can't ditch this BGA

Well so far so good. I initially removed all the BGA on Sat, but it nearly grew back on Sunday. Amazing how fast it grows. I did the blackout last Sunday, honestly got lazy and didn't bother removing the BGA that grew back. Turned the lights on/ uncovered the tank Weds evening/ I was afraid to look, but the fish were still alive- sigh of relief- and all the BGA was erased!! Also Cleaned out the filters especially the Eheim, which hadn't been changed for a couple months- It was pretty dirty! At any rate the moss, which was most effected looks better than ever. I'm really pleased with the results. Now that I am keeping my macros up and plan on not slacking off on the filter maintenance as much I don't expect to see it come back. The only algae I'm dealing with now is BBA, but I'm gonna try to raise the C02 levels to 40ppm and see what happens. This is according to the charts, but I doubt that it is really that high since the tannins in water may be throwing it off slightly. We'll see what happens.


Thanks!!

Jeff