There are two types of 6″ net pots commonly available on the market. Avoid the style on the right if using a hole saw as they will fall through 6″ net holes. These undersized net pots can usually be identified by the two tabs which do nothing for keeping it from falling through.
I used to run water level indicator tubes too as most online tutorials have them (especially on YouTube).
I now advise people to avoid them like the plague. The small benefit they provide is greatly outweighed by the risk. They sit outside of your water reservoir, so the water in there gets warm and stagnant (it is not being actively oxygenated by your airstones). This is a perfect breeding ground for bacteria that can later spread through your system and cause root rot.
I wish I did not drill those holes in my water reservoirs when I first got started with DWC as they were a pain to patch. Credit to reddit user Trees for Life for the photo above.
Many builds for DWC recommend the use of 5-gallon buckets (looking at you again YouTube). They will work but I do not recommend it at all. The 5-gallon bucket is simply not large enough. It negates one of the primary advantages of DWC- which is the ability to leave the plants without attention for weeks at a time. I have a friend that has to fill up his buckets daily during peak flower… might aswell be growing in coco or soil at that point.
Another drawback of the bucket system is more swings in pH and water temperature. A larger volume of nutrient solution is more resistant to these swings, especially when it comes to water temperature (which should ideally be 68F and never exceed 72F).
I used to reccomend people get the biggest tote they could get their hands on. After a friend setup a 480 Watt grow using a 60 gallon tote I learned that there is such a thing as too big.
The primary disadvantage is that with so much water you are going to go weeks at a time without a top up. This increases your likelihood of contracting root rot as the water is not being depleted at a fast enough rate.
The second disadvantage is that it’s a waste of nutrients. Using my calculator he was using up LITRES of nutrient solution at a time. He would often have leftover water when needing to switch the nutrient ratios to another stage of growth. For these reasons my favourite size of container is the 15-17 gallon tote. It is the perfect match for a 240W LED Panel.
You can see below what is possible with one of these totes (24k from one of my most recent harvest):