Here's my setup:

(The paper has now been replaced with paper plates)

Anyone?

My res temps are between 66 and 69.8 at given times throughout the last couple of days - is this too warm? I'm not buying a chiller, so should I buy hydroguard or make up a microbial tea?

A few things Ive come to learn.

Source water MUST be free from nasties, if you have any they can explode in a DWC system because its perfect conditions, I run a UV sterilizer and 2 filter system on my source water, this was a game changer for me.

Plastic totes heat up quick you gotta have them insulated even the lids are fluctuating heat source it eases up once the canopy covers it but can be a disaster kicking of with clones etc I was getting big fluctuations in the root zone which I didnt like, I thought I would try and get the root zone temp as stable as I could like soil affords but in a RDWC system, I did away with thin plastic and built a large tank out of cheap pine railway sleepers giving a 50ml wall thickness, its is a box 1200 wide x 2200 long x 500 deep, water level 400 deep, I lined the box with pool liner. I have a chiller on the system and it rarely turns on because inside the tank its so insulated, my epicenter is in another room built the same way, the chiller is in the epi center room not the grow room.

I also run Hydrosil Ultra which is a Peroxide+silver product for sterilizing drinking water, I put this in the system every 3 days.

When you say youre not buying a chiller, man for DWC you really do need it, if you have a hot summer then its even more beneficial because the cooler root zone allows the plants to handle a higher ambient temp better, I just think make it so it runs really efficient.

And for the UV system it guarantees clean water to begin with, I think source is a major problem for a lot of guys with consistent root problems.

The Peroxide is to make sure I catch whatever comes in after the UV, the system is now running extremely clean no scum growth any where the roots are like snow and massive.

I have an air pump feeding 12 airstones laying on the bottom of the grow tank, Ive heard people say it brings in nasties to your water, I dont believe that because your water surface has the same air contact anyway, I dont believe bad stuff comes this way, its more from contaminated water and or rotting stuff in the system, or the plants themselves had it on some roots .

Prevention is the key get it dialed in and its a great way to grow, but if you got any weak spots it will kick you in the pants.

You’re not a Youtuber are you? Just watched a video from a guy called HeisenBeans who said pretty much everything you just said, from source water to UV.

I think my source water is pretty good actually. 0072ppm and 144 EC