Well the Cory died about an hour after I posted this. I really couldn't say about his colour for sure but if there was a change he was maybe a tad darker. I also put another female down with clove oil as she was fluttering around on the bottom and  her gills looked swollen. I know at this stage there is precious little that can be done.

There is definitely no sun hits that tank. I am now getting up way later than the old 4.30 but I still get up with the sun and in the afternoon it hits my pc monitor which is a bit of a pain but forces me up out of my chair for a bit. I was telling unc in an email that we've had a bit of a heat wave here where it was 34°c (97F) in the kitchen 4 days in a row and it's only spring. It's eased off now thank goodness. During the heat I was turning the lights off during the day instead of at night but all up they're on for about 12 hours a day same as always. I also remove the glass cover during the hot days and top up their water with rain water which is cooler out of the tank.

I did a big cleanup in there today. I even found a tiny fry in the filter which is one of those waterfall types! I removed the two creek plants (?aponogetons) which were looking worse than the purchased plants as they are only new and haven't had a chance to die with my care yet. The root system on those 2 plants was incredible and took up probably 1/3 of the tank bottom. I trimmed the plants down to about 1cm tall and trimmed the roots and replanted them after gravel vaccing up most of the gunk.

The algae is dark green and looking with my glasses I suspect it's bordering on having a dark blue tinge :(  It is on the gravel, the glass and the plants. The nitrates were about 15 but the pH was over 7.6 so I used a little more rain water than usual for replacement water.

I suspect it is the old diseases coming back to haunt me now that the fish are maybe more susceptable because of their age. What is left in there tonight looks healthy, even the old girl with the very bent spine. I put my 4 female fry in there as I had to put them somewhere and they came out of that tank only about 8 weeks ago.

I'll get in and re clean/rinse the filter sponges tomorrow as that's a good idea of yours which didn't occur to me and there was quite a bit of green flakes floating around by the time I finished to day.

You know one of the things I really love about the guppies is their curiosity and lack of fear when I do anything in the tank. The silver dollar on the other hand (in another tank) is so stupid that after 2 years he can't figure out that I'm not going to hurt him and that water changes occur at least weekly and that someone walking past the tank is usually bringing food and not about to commit a crime on his fish body. Duh!