Good morning,

I've moved your thread to the Livebearers/Guppy section of the forum.
If you would be so kind as to complete your Aquarium Profile information it will be a great help to others. You can access the profile by clicking on My Settings in the blue bar close to the top of the screen. In the drop down box click on Edit Aquarium Information.
Here is a link on acclimation that you will find very helpful:
Acclimating Tropical Fish to Your Fish Tank
As stated above, your guppies are tropical and really need a filtered, heated home.
Are you aware of the
nitrogen cycle that is crucial to fish keeping? Link below:
The Aquarium Nitrogen Cycle
Do you have a
test kit? The kit that is most recommended is the
API (liquid) Master Test Kit. It will test for everything mentioned in the Aquarium Nitrogen Cycle link.
To cure the ICH:
Raise the temperature in your tank to 85 degrees. Leave it there for a full two week period. Higher water temperatures require more oxygen so an air stone/air supply line is needed if you aren't currently using one. Do two gravel vacuums each week to remove the ICH spores that fall off the fish and into the substrate. Note: Ich may appear worse before it gets better. Be sure to keep the temperature raised for the full two weeks even if the fish appear to be free of the disease. The increased temperatures interrupt the life cycle of the ICH and they die off.
ICH is caused by sudden temperature fluctuations and stress as mentioned in previous posts.
I hate my post is so long but I felt it was necessary for the health of your fish. If you have any questions don't hesitate to ask. I know it's a lot of information to throw to you at one time.
Best wishes!
Ken