Your filters stopped and then you restarted them? Were they off a long time -- a day or two -- and then restarted without cleaning? It's a question of balance and your teeter must have tottered ;-) In any event, it sounds like a good old fashioned algae bloom. If it was caused by a spike in nitrites or more likely ammonia/ammonium due to filter failures, then you must have the cause under control. So you just want to clean up the soup you have. A UV works great for this, but if you don't have one; it's a terribly pricey solution. If you do decide to buy one, don't get one of the Custom SeaLife models that vendors are trying to move out the door -- CSL folded and provides no warranty support and the CSL UVs, imo, need warranty support. Diatom filter should help speed up the subsidance, although I've found these a bit less effective. A 4-day blackout ought to get rid of it. The is very inexpensive -- you even save on the electric bill ;-) Whatever method you choose, start with a good healthy water change and have good filtration to pick up the algae that is going to die off. If you have a bacterial bloom mixed in with the algae, that won't be affected by the blackout, but should be affected by UV and also by a diatom depending on the diatom filter. However, even without UV or diatom filters, a bacterial bloom will subside on its own after water conditions get back in balance. You might have to wait a few weeks for the bacteria to clear up. It might clear up very fast if your new (or renewed) filteration is seeded with some good mulm or some of the old biomedia from the old filters. If there is BGA mixed in the algae bloom, you'd probably see signs of it attaching to stuff, but a blackout should work wonders on BGA too. None of the methods work for any length of time if the water conditions are not in balance. Let us know what works for you, sh --- rspahn@sackets-harbor-high.moric.org wrote: > Hello and HELP! I have a planted tank with a severe > case of blue- > green water. The plants are in fine shape. How is the > best way to > clear up this tank? The tank has been running for years > without any > algae problems. I think the problem was caused by the > two Fluval > canisters slowly dying at the same time. Thank-you, Ray ===== - - - - - - - - Field Trip to the Baltimore Aquarium and The Aquarium Center First event of the AGA Annual Convention Nov 12, 13 & 14; Details & Registration at www.aquatic-gardeners.org & www.gwapa.org __________________________________ Do you Yahoo!? Win a $20,000 Career Makeover at Yahoo! HotJobs http://hotjobs.sweepstakes.yahoo.com/careermakeover ------------------ To unsubscribe from this list, please send mail to majordomo@thekrib.com with "Unsubscribe aga-member" in the body of the message. Archives of this list can be found at http://lists.thekrib.com/aga-member/