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Discussion Starter · #1 ·
I have new tank of 2+ months. GSA has been my only issue so far. Contrary to advice out there that low phosphates and unstable CO2 are the causes, my deposits reduced considerably when I upped nitrates. I could see the difference in a day. However it still deposits a little daily. Not sure if this is something my tank will "grow out of" or not.

I have been gradually upping nutrient content in the water column. I had been running all nutrients down to 0 each day and then replenishing, which I think that and high light helped the GSA get started. I am currently boosting both phosphate and nitrate nominal PPMs and currently measure about .8ppm phosphates right before I dose daily (lowest point). Based on phosphate measurements (I use a Hanna HC which seems fairly accurate), my tank is consuming ~.3-.35 PPM phosphates a day. I am going to continue gradually boosting phosphates maybe to 1.5PPM nominal to see what happens.

I'm guessing my nominal N (nitrates plus urea that Seachem puts in their Nitrogen) are now about 3-4PPM (all nitrate tests suck). My tank appears to consume 2-3PPM nitrates per day. I have been putting 3-4PPM in daily to gradually raise.

CO2 is very stable and on a ~.8pH drop program (so maybe 20-25PPM CO2) via pH controller. I will not go more than that as I have no interesting in stressing my animals nor do I want any more growth. Growth is already too fast, I have to trim carpets and stem plants weekly or they overgrow quite a bit. My stems will hit the surface, bend, continue growing across the surface and shade most of the tank all within 7-10 days.

I dose Excel daily at the daily dosage prescribed on the bottle. I don't believe this has any effect on GSA (nor GDA) but just mentioning that I use it (and another reason I don't feel a need to have absolute max CO2).

So my two questions are:
1. What should my next actions be to further reduce GSA deposits. More phosphates have not seemed to have any effect on it although I will continue to slowly raise the nominal phosphate PPM to see what happens. I know I can reduce light a little. I have two Fluval 3.0's on my 50G and have reduced both from max considerably. It's easy enough to reduce light a little more if I need.

2. Most important, are there any tricks and easier ways to scrub off or otherwise remove this algae? I have an acrylic tank, so razor blades and metal scrapers are out. I use nylon API scrubby pads on a pair of long locking forceps to scrub it. And let me tell you, I am in great shape and work out with weights several days a week and it is a freaking workout scrubbing the green off! You have to scrub hard and stay in one little place for several seconds to get it all off. I have a lot on my Anubias plants and driftwood that I am just going to see what happens and leave for now. The problem with this stuff is it is too hard for inverts to do anything with (I have shrimp and snails), it seems to stay there forever until you clean it off. I may try a magnetic scraper although a bit concerned about those scratching acrylic (they can trap sand and other stuff that can then scratch the acrylic).
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