Here's how to solve your problem. Spend some money and get black plastic pots with holes at the bottom for good drainage. I reccommend Sunshine Mix #4 it's a great soiless mix and has good aeration. You need to let your pots dry out pretty well before you water again. I water every 2 days. Stick you finger into the soil, if it's wet DO NOT WATER. Wait until you stick your entire finger in there and it feels bone dry, then you can water. A good way is the finger test and actually lifting the plant up, if you lift it up and almost hit yourself in the face because it weighs nothing then you can water
Don't be afraid to let your pots dry out, they will thank you with amazing growth and the leaves will be pointing straight up like they are praying. a PH of 7 is too high. 6.5 for soil mixes is perfect. Just follow the basics, good aeration, good drainage, stable temps and great airflow. Humidity should be 50% MAX. 40% is better. When I say I water every 2 days that is for my flowering plants that are 2.5-3 feet tall and growing fast and producing big buds. You may not have to water for an entire week depending on your situation.
this is also what i do, every morning/day i go in my room the first thing i do is pick up all my plants, i can tell by their weight if its time to water or not, place a few holes in the bottom jut to be sure nothing is just chilling downthere, like dude above me said, stick your finger in the soil like 2 or 3 inches, it should be dry or at least mostly dry with a small amount of moist and then you can water.
Put is this way, its much much easier to over water cannabis and all plants in general than it is to under water them, and when they are underwatered, you will know immediatley they do not like it and will droop badly letting you know.
If I were you i would drill holes in the bottom if you havent already and stick a fan in there maybe when the light is on to try and dry it up in there, I wouldnt even go near those pots with any water at all, you might not have to water for 4 or 5 days if its wet enough. My plants are about 3 to 3 and a half ft tall, 3-4 week flower very nice size buds in 5 gallon pots, i have to water pretty much every 24 hours, if I give a good watering more than avg. than I can get away with 36hrs-2days without watering, but after that eh, its anyones guess, you will get a feel for it as time goes on, dont worry. Like I said, i made it a habit to open my tent everyday or whenever maintence work was to be done and the very first thing that i did was lift plants and stick my finger in the soil, I dont need ph meters, i dont need ppm meters even anymore, I have both, but rarley use them, basically once in a great while ill have a small def. or small over nute and only then will I inquire about my ph and ppm (EC) levels. Now, im not recomending you do this as like I said, I have been at this for a decade or two lol. I used metering equipment when I first started out to, especially when I grew aero or dwc. I prefer soil these days only because I live in an area with unfavorable water but even still I use no equip. with my soil girls and have NO problems at all. I use basic GH nutes and even sometimes cheap NPK shit from the store and it works awesome, I can promise my buds have the MOST amount of crystals I have seen in ages with only 25 days or so flower. If i was doing hydro I prob. would use my metering equip more, just my 2 cents man, I hope i said something that can help you, and like the gentlemen above me and I said, use the finger trick and as you do this you will get a knack for it, I promise, Good luck dude..