Help! Ick treatment ineffective!

[Calypso mermaid]

Hi,
I posted here a few weeks ago when I brought home a sick little loach with skinny disease. I treated him successfully and he recovered completely.....he's still a little thin and wierd, but he eats like a pig and is strong and active. However, on the last day of treatment, I posted here because I broke my heater and so my fish developed ick.
I went out and purchased Maracide, with Malachite Green and Chitosan and read the stickys here on this list. I turned the heat up and treated the tank with a lower dosage due to the warnings about loaches and their sensitive skin.
Sunday I was shocked to wake up and find one of my loaches covered in ick! I guess the low dosage treatment didn't work, so I again did a big water change, removed the carbon and dosed the tank at full strength. Problem is, the treatment doesn't seem to be working. This morning, I did a water change and vacuumed the gravel well and added the second dose. I just arrived home to find another one of the loaches covered in ick! Why isn't the full dose treatment working now?! Let me also say, the two rainbow fish and pleco have remained symptom free through this whole ordeal. Have I created some drug resistant strain of ick on my loaches?
Last, my pleco that came home the same time my tiny sick loach did, has quadrupled in size-I'm not exaggerating.....and he poops constantly.....I know they get big and actually plan on just upgrading his tank to fit his needs....but I'm flabbergasted he's growing SOOOOO FAST!!!! It's almost like a bad science fiction movie where the drugs I put in to save the loaches had a mutant effect on him. Is this normal? Can someone give me more info on plecos? I found a chat board regarding them, but got lost on the the numberical identifications and just lost interest.

[newshound]

removed the carbon and dosed the tank at full strength.

I had ich once used coppersafe and my problem was gone.
ps-it was in a planted tank. I never use carbon.

[poeticpyro]

you've got to give the meds time to work... if you keep dosing daily you may do harm to the fish. just medicate 1 time, turn the heat to like 84-86, keep the lights off *reduces stress* add the airstone, remove carbon, and wait... i had ich last week.. it is now gone. patience... it's going to get "worse" before it gets better...