Little tanks are just a lot harder to keep balanced than larger ones. They may need even more partial water changes. (Do as I say, not ...) ;)

I recently set up a couple of small batches of killie fry in small "turtle bowls." Soon the larger fry was exiled to his own 1-gallon wide-mouthed pickle jar. All of the fry containers were set up with water from established  tanks and left in a well lighted area. This allowed me to squirt newly hatched mosquito larvae in there and monitor when they were all eaten. I have also been adding a little flake dust.

WOW! Not only did those small containers turn bright green (Happy St. Patrick's Day!) but they developed a slimy algae which is forming colonies in the bowls and a skim on the surface. Never had that combo before! Before feeding, I have to squirt holes in the top film or lay some b&w newspaper on the surface to draw that stuff off. (And before tossing it, I look for fry stuck to the newsprint!)

I don't think that includes Cyanobacteria (blue-green slime) but I have never had such a rich culture of organic "stuff" bloom like that. I have been lucky though because mother nature has found the means to absorb the waste material while  shouting at me, "Scott you idiot! Give them proper habitats!"

Treating for Ich may not hurt, though some Ich treatments have an antibiotic in them and that could trash your nitrogen cycle. If you shine a flashlight on the guppies and don't see white spots, don't stress the fish with a treatment they do not need.

If you shine the light on them and there are really, really tiny spots, gray to gold and looking like a sheen, that might be velvet. That does sometimes accompany the feeding of b.s. But it is more likely with guppy fry or with several other species of fish (killies, rainbows, bristlenose "plecos", Bettas, gouramis...). If there were fry in the tank and they "mysteriously disappeared" and then the adults began to clamp a little, that is a prime set of reasons to look for velvet.

If you do partial water changes three times a week and have viable, little filters in there like a sponge or box filter, the scratching should go away. If it doesn't and you wish to treat for parasites, try one of the mixes like Jungle's treatment for internal parasites which should also deal with external ones.

It probably has Praziquantel in it and that will help. (I applaud them for now listing contents.) It will also have an antibiotic or two in there. That may clobber your nitrogen cycle. Feed sparingly. Maybe do a 100% water change from a healthy tank and re-treat, (I'm sooooo good at spending other people's money!) Leave an airstone in each afflicted tank.

Of course don't use your siphon or bucket or other equipment (hands?) used there with other tanks until you know if the problem is just nitrogenous stuff. They (the siphon tubes) could be left out in the summer sun and then into in a salt solution. (See below.)

In the meantime cleanse your filters and airlines. A 1-10 part  bleach to water solution will work (outside in the shade, maybe in a covered bucket) for the plastic, Or do a day's soak in a hyper-saline solution for the box or sponge filters. (Sponges will be quickly destroyed by bleach.) Since roughly a cup (16oz) of salt per gallon will give you a marine mix, maybe slightly heap that cup with salt. :)

Then rinse and get those filters going in your established tank so that they are bacteria laden when they are needed in the small tanks. At the end of treatment do a 100% water change. Either fill the re-establish tank up with water from another tank or do a 60-40% (old, new) water mix.

You mentioned using activated carbon again. I think you know this, but for someone looking on, the activated carbon is usually used up within a week. When put in distressed tank, it is probably maxed out even sooner and should be removed before doing a partial water change. It will absorb ammonia and medications while it still has the capacity to do so. I think your depending upon biological filtering and partial water change during "usual" conditions is wise and probably gives you a better bang for the buck.

I wonder if using activated carbon, Ammoniasorb or Polyfilter to remove waste material in an emergency has any effect upon the beneficial bacteria. If someone enjoys fiddling with test kits, would you please test a tank after it has been filtered with a serious ammonia absorbing resin? I wonder if after the activated carbon or whatever has been removed if there wouldn't be an ammonia spike of some sort because some of the beneficial bacteria has starved.

Of course, one could pack the tank with plants. I have a bucket of Salvinia natans, which the schnoodle and I clean last night. (He supervised, I turned the floating plants upside down in water, while feeding the adult mosquitoes, so as to float most duckweed out of their root mass.) Outdoor plants sometimes shock because of the more modest lighting indoors. We'll see...

I'm glad to see you again on GL G ma. I am sorry about the circumstances.

You are not alone in struggling to get on Guppylog. hat stinking
Internal Server Error message
is driving me crazy too. Sometimes arrowing back and trying again works. I've also hit the refresh button at the top of the browser page and often that works.

My computer's C drive is close to needing to be reformated. I just don't want to go to the trouble right now of reloading Windows XP. As a quick fix, I get off line and run a maintenance program (system mechanic version 6, soon to be 7). Rebooting the computer and getting back on-line helps some.

The site's server is getting old. Scott Lockwood is doing what he can/ He has been quick, when asked, to tweak it again. I don't have the money (or the need) to hire a site from him and increase his cash flow. :(

Maybe if we all click on his advertisers more. ;)

By the way, I had just finished whining about northern Illinois' heat and humidity in response to the diary before yours and then, there you are, from Virgina. I can just hear you, "Midwestern Wimps!" ;)

By the way, if a tank has a really efficient population of beneficial bacteria can really break down a dead guppy quickly. And even though our home is relative bug free, some bodies I'm sure have been scavenged by wandering crickets after lights out. (And then there are dogs and cats...)

Hope to see you on GL again with the successful story of how your gups have stopped scratching. Please keep trying if there is trouble getting through.

Gotta go. And you can bet that lots of water changes are on my "do list".