Some persoanlized humidity assistance needed please.

Did you close the vent holes ?
 

pie pan or stove eye covers work great for large surface area. 

I don't know which foam incubator you have or what your water reservoirs look like or which might be available. So I can't give you too much specific advice pointed toward your specific incubator.

Humidity is mainly controlled by water surface area. You can also affect it by opening and closing the vent holes, but during lockdown those need to be open so the chicks can get air to breathe, especially with a still air. By adding the tuna can and the washcloth, you increased the water surface area so your humidity went up. But different things may have happened.

You may have gotten other areas of the incubatior wet when you put the tuna can and wash cloth in there. The humidity went up until those extra areas dried.

The washcloth may not be a perfect wick. It may not stay soaking wet but just sort of damp from the wicking. So once everything stabilized, the humidity in the incubator dropped some.

Your water reservoir may be going dry. With the washcloth wicking out the moisture, the water gets used up pretty fast.

I put together some of those straws with an accordian bend to make something I can go in through a vent hole and reach all my water reservoirs. I got a syringe from Tractor Supply that I use to put water in that straw. So I can add water without opening the incubator.

If you have other water reservoirs available, you might try adding water to them. You can try adding water to the tuna can and see if that helps. Or you can soak that washcloth and see what happens.

And check to make sure your lid is on tight. I've made that mistake and the humidity dropped, although the temperature stayed stable.

Good luck with it. Hopefully you can work out a solution with your specific incubator.

I'm here in Florida myself. 70% humidity is a little high unless you have something unusual going on. I shoot for between 60-65% myself which it sounds like you are at.

If your box is fan driven and you just have to have the humidity higher then leave the set up as you have it and mist the interior of the box LIGHTLY with water. Just a spritz or two, not enough that it runs off. That will kick it up the few extra percent that you want. Should not be necessary more than a couple of times a day and likely won't be necessary at all again after the eggs begin to hatch.

This is what I do.