This may be the blind giving the sighted advice, but when was the last time you back up everything (to a storage something outside of the computer) and reformated your hard drive? Basically that is removing (in my case Windows XP) and reloading it, then reloading all of the other software on that drive, since they got removed with it.

Our local computer club recommends doing that annually. Even though XP seems far superior to previous Windows operating systems, software still corrupts and needs to be reloaded from time to time. (And then one spends an afternoon reloading the updates.)

A guy who has bailed me out a few times (he says he loves to look at my computer and investigate messes he has never seen before) suggested that since I have two internal hard drives, I should put all of my software on the C drive and everything else I wish to save on the D drive. We agreed that the D drive should still be periodically backed up to an external hard drive.

That way if the C drive goes cablooey, hopefully everything in D is still there. If the C and D go away, the photos, articles and comments saved to D are still extant and can be copied back.

Sorry about only having the 10-gallon set up. After your wonderful 75, I can imagine the withdrawal symptoms! Cyanobacteria blooms when there are too many nutrients in the tank. IF and that is a big if, we can lower the nutrient level in the aquarium, the higher plants and biological processes "should" be able to out compete the Cyanobacteria. I will admit "Nutrient Removal," frequently mentioned by David Boruchowitz, about says it all.

I'm going through much the same thing that you are, but on a greater scale. The living room 55, which was torn down after a decade or two and re-set and sort of planted, has become a mess. The natives in it are doing surprisingly well. But the low light plants can keep up with the nutrients and there is too much Cyanobacteria in there.

Ironically the green slime may be absorbing all of the extra nutrient stuff in the water and the fish have been doing well. Two weeks ago a buddy offered to take some of my killies and enter them on my behalf in a show in the Detroit area. It took most of a Saturday evening to catch a single pair of Fundulus notatus from that tank. By then it was half disassembled and a process if removing the plants, rinsing and piling them in a 10-gallon on the floor had begun.

Several partial water changes and the disassembly, cleaning and re-setting of the internal power filter have taken place. As time permits the plants have individually been scrubbed down by hand under the laundry sink tap. Because of other responsibilities, the tank was left as in, but going on a wait and see mode.

Before I could even get the rest of the plants in, that green slime started again on the gravel! It has once again been gravel vacuumed and more, unexpected dirt was removed. The plants are being returned. About 60% of the tank's surface has been covered with Salvinia natans. (I have extra gallons of the stuff from outside.) The lights are on more and the hope is that their hungry roots will soak up the nutrient removal process will clean up the water and tank even further.

Some water treatment facilities are experimenting with scrubbing the water with water hyacinths. That must be outdoors or under incredible lighting. IF those plants are doing their jub, they will multiply so fast, that many will have to be composted.

That is exactly what the Salvinia have done for the container "gardens" outside. Even the depredations of the raccoons, when they can get through the screening, can't keep up with them.

It is hard to throw extra plants out. (Why is it that with most garden items, we either have too many or two few?) But at a certain point, tossing them so that the surface is somewhat clear for oxygen exchange and so the other higher plants can get some light, is good.

Ah! Cyanobacteria doesn't do as well when there is agitation and current to the water. I'm trying to fit a powerhead to a modest sponge filter. That would go on the opposite side and end of the 55.

Interesting point about nitrates having no smell. But the products growing from them - Cyanobacteria or cloudy water or worse - may.

Could a little hornwort be of service? Although in extreme cases Cyanobacteria can grow on it, the green slime usually washes right off. Hornwort grows pretty fast (and dies in the bag if we don't get it out quickly). Hornwort is one of those plants that produces allelopathic chemicals which are mildly poisonous to other plants (such as some algae) and keep them at bay.