Spirogyra Algae - What else can I do?

I am loosing a long war with Spirogyra algae and am hoping someone here can offer some insight into what I might be doing wrong.

The tank: ADA Mini-S
Filtration: The smallest Eheim ECCO
Substrate: AquaSoil I - Normal mixed with powder
Tank established in: October 2008
Critters: CRS, Snowballs and Amano Shrimp + a Nerite
Other: Chiller set to keep things between 71-73 degrees, ADA Mini-S light with ADA bulb (27w I think) on for about 8 hours a day, pressurized CO2 from a 2.5lb tank, through a DIY reactor, plumbed after the chiller. CO2 measured with drop checker - set to run the thing green on a timer - comes on 1 hour before lights on, and goes off 1 hour before lights out. Water is RODI, reconsistituted to 2 kH (with baking soda) and 3 gH (with Seachem Equilibrium). Water changes are done weekly - and I stopped dosing any ferts into the tank many months ago.

Plants: lots of stuff... mini clover, star grass, blyxa japonica, mini pennywort, elantine triandra, a few different mini mosses, mini pellia, dwarf riccia, etc - all in small quality. aside from the star grass there are no stems and even without ferts the plants have been ok - for the most part.

I recently moved (back in April of this year) and ended up neglecting this tank for perhaps a month in the process. I had a history with Spirogyra in this tank that I thought I had conquered about a year ago, but with the neglect it bloomed back into a full blown bowl of Spirogyra soup. It was so thick it was all you could see in the tank. So I removed as much as possible and trimmed everything back to a maximum. I then added 30 Amano shrimp, who made quick work of the remaining spiro...

A few weeks later it started to come back up in the mini pellia, the mosses and the dwarf riccia and the amanos started ignorning it or just not keeping up. I then started a new series of black outs that I have been repeating ever since. First couple were done for 3-4 days at a time, with a week of recovery time for the plants. This would beat it back, but then it would rebound within a week or so. I have now extended my blackouts to 6-7 days at a time, which is starting to have a negative effect on my plants - but I still can't beat this stuff. I don't feed the tank, and after a very long blackout I can usually only find a strand or two of it, looking white and brittle - but again within a week it is growing like mad again, and from everywhere.

I do water changes before and after each backout. I turn the CO2 off during backouts. I do not feed the tank. I remove as much as I can manually everytime. I don't fertilze. Why will it not die? I am now considering a 10-15 day blackout period. I would prefer not to loose all of my plants or to add any chemicals that would trouble the CRS. I have tried Phyton Git with no luck on this stuff.

It seems that I may have created a super strain of this algae and I really can't figure out how to get rid of it for good... I have read others beating it with the methods I have been repeating. What am I doing wrong?

EDIT: forgot, I also used FFF for a while, and they are very effective at eating it. Unfortunately they also try and eat the shrimp. And they never did rid me of the problem, so out they have come. The amanos also tend to crawl out of the tank, I think I am down to 10-12 now. Considering throwing another 20 in there again to beat it back - but this has not yielded a permanent solution in the past either...

 

Thanks for the initial feedback.

No surface scum - and the ECCO is rated at over 100gph on a 3.5 gallon tank. The flow is so strong I have to throttle it back. The filter is full of the eheim coco-puff looking stuff - I could rinse it out. No floss or pads.

Here's the tank earlier this year, after I thought I beat the Spirogyra the first time:

http://www.azaquaticplants.com/community/showthread.php?t=9001&page=5

I will try and post up a picture of what it looks like now tomorrow evening.

I was dosing EI for the first year - when I had the big problems originally. CO2 is dialed in and stable. I noticed that the Spiro would jump back more quickly if I dosed after a blackout, so I have backed away from that. I even notice some bounce from whatever traces must be in the equilibrium mix after a water change.

A side note - I have been running all of my tanks, since 2006 on EI with great success. This one is the first on the verge of failure...

 

Interesting.... Even with no spiro I would be running the tank lean for the CRS - but perhaps I should reconsider dosing and 24/7 CO2...

 

Last blackout was for 6 days and ended either Saturday or Sunday (I am loosing track)... The Spiro was almost completely gone. Just a few days later and it is back with a vengeance. Left unchecked for a whole week and it would be horrible.







I just did another large trimming of the mosses, etc - did several water changes - using about 10 gallons of new water and emptying/replacing the water the in tank several times.

I also opened up the filter, which was a little sludgy - cleaned it out and added some nitra-zorb.

Just ordered 30 more Amano shrimp for good measure.

Can healthy plants really out compete this algae? Can anything save luck beat it? I have beat it once in a much larger tank after a major blackout, Excel OD and a massive trimming. Maybe the smaller tank is harder to win? Maybe the mosses are the problem?