Possible Overwatering problem, help!

If this is as simple as an overwatering problem I would be happy. Please tell me what you think. I grow in a coco/perlite mix(mainly coco). I use 5 gallon pots and the botanicare products. I only use about a gallon per plant/once a day right now so it doesn't seem like I'm overwatering. lately the plants have been holding water and staying wet even at the top of the pot to the point where they really don't need to be watered everyday which doesn't make any sense. Six months ago, I was watering them twice a day because they were taking in so much water and the cola's were huge. I've had some fungus knat problems recently which might be part of the problem too. I just started using Azamat for that. The buds aren't fully forming either anymore which is probably because the plants aren't using the water. I've kept the ppm at about 1500-1600 and ph at 6..

What are some possible problems do you think might be causing them to hold this water and not allow the buds to fully form? Any suggestions would be greatly appreciated.

weed likes drainage, a 5 gallon pot should be leaking at the bottom after a gallon of water, thats what you want, my 5 ers get watered about every 3 days avg.even wait till the leaves wilt a little is better than overwatering,
drainage seems to be your other issue, the soil needs some perlite or vermaculite mixed in to loosen the soil
or maybe its rootbound?

Thanks for the response!
There's definitely good drainage. I use this mix called basement(made in humbolt) that is a mix of coco/perlite. If I water with 4 gallons, probably 2 1/2 to 3 are coming out. So, you think I should cut back to once every 2-3 days? Is there anything else you can think of that would cause the plants not to process the feedings?

can anyone else give me suggestions?