Reservoir Change

So I’m very new to DWC (as in this is my first attempt). So I have a very simple set up, mostly because I wasn’t expecting the clone I received to be in a rockwool cube in a net pot.

So I have a black 5 gal bucket with a larger diameter circular air stone pumping a ton of O2 in there, and I’ve been using hydro guard because I have no way to regulate the water temperature. So far the roots are huge and healthy, as well as the plant.

So my question is, I’m about to be starting week 3 of flower and this thing is a monster bush because I didn’t prune it as well as I should’ve in Veg (working on it).

Is it safe to top off the nutrient bucket? Or should I keep fully changing it every time like I have been?

Im interested in avoiding nutrient buildup so that’s why I keep fully changing the buckets, but maybe I’m just being a helicopter parent.

So if there’s any seasoned DWC veterans on here who can help a brother out I would appreciate it!



This is where a TDS meter is handy.

For example: bucket full, day 1 @1,000 ppm. Day 2, bucket is down 1 gallon and TDS is 1,200 ppm. Add water until TDS returns to 1,000 ppm. Scenario 2: same full bucket day one, day 2 the TDS is 800: mix a gallon of nutes at normal TDS and add. Every two weeks, change rez.

DWC is problematic as you need to keep rez level stable at 1 1/2 to 2" below net pot and allow air stone to send micro-droplets up into hydroton. Adding a reservoir changes the dynamic dramatically; especially in flower when a plant can drink 2 gallons per day. To me this wastes the opportunity of running hydro which is ‘low maintenance’. Not the case with DWC.

If you cannot control rez temps you will almost inevitably develop root rot. If rez temps are over 70F you will be fighting root rot.


I mean as far as I can tell they are healthy. I have to have someone help me take a picture of it while I’m holding it up, or set a timer or something. So I’ll figure that out and post a picture.

I tested the reservoir temp after I read that because I couldn’t figure out why I didn’t have root rot.

And it read between 20-21 Celsius(68-70 F). My average tent temperature is 73-77 F, so I guess maybe since the air temperature in there is remaining constant around there that’s what’s keeping my reservoir temps in line? Also it’s always slightly colder at the very bottom of the tent.

I just wasn’t planning on running this set up so I definitely couldn’t afford a chiller. I’m pretty handy so I looked into making one with a CPU water cooler but I haven’t had time, nor have I been forced to by unhealthy roots. My only other idea was if it gets too hot maybe ice? I’ve seen people talk about that but it seems really risky. My apartment gets really hot when it’s hot outside, so I’m worried about June and July.

Also I may not have been filling the reservoir up enough…I’ve only been putting about 3 gallons at a time in a 5 gallon bucket, so I’ll measure that next chance I get.

Thank you for the info it’s super helpful!


That’s perfect. The climate I’m in also keeps rez temps around 67F without help. You can also put a sheet of Styrofoam over the buckets to reduce radiant heat (lights) warming it.

Hydrogen peroxide is your friend in hydro. Diluted down you can rinse roots at rez change which will keep things happy: 15 ml/3 liters of 3% peroxide (in the States it’s under $1) will keep everything sanitary.


Absolutely very well put! This is why you are the man!!… haha!

BTW, if myfriend can’t help you, no body can! :+1:t2:
If I might add, try to keep water level around an 1.5” from the net pot. She needs the air inside the bucket.

Good luck!


Kind words!

Remember I’m just another old stoner haha!


I actually have some of that reflective insulating wrap for work so I could use that to wrap the bucket!

Good idea!

And I’m definitely going to start using the peroxide solution as well. That sounds like another awesome way to maintain root health.

I’m not gonna lie being forced into trying this out has made me decide my next grow is going to be 2 DWC plants. The growth is insane! The main stem is like small tree sized haha.

But next time I’ll be a little better prepared lol.

I’ll just have to come straight to you with my problems next time @Myfriendis410 !


As long as i could keep my water temps under 75 i was good here. If water spiked over 75 then issues started to show up. I gave up on the hydro buckets for now. Water chiller i believe is a must if u run hydro otherwise u just ask for issues. Hydro guard worked well for me to get thru the grow but i wont do any hudro wothout a water chiller or being in a basement where the bucket has a way of staying cool like it should. So gar ive found coco and soil to work for me and coco i believe is the winner of the 2 as it does alot better for me than soil has so far. Smells better also than soil does. No dirt smell only nutrient smell and i love the smell of some of the nutes. Like floraliscious plus. Smells so good to me. My wife hates it she says smells of prenatal vitamins lol


Yeah the highest I’ve seen my temps get is 78 degrees when it gets really hot in my place.

I’ve essentially made a makeshift ac unit for when that happens and I’ve since wrapped the bucket in reflective insulation

Essentially it’s one of those turbo fans with a basket I’ve attached to the back. I put a bag of ice in the basket and take some duct work to the front to run it straight to the tent lol. It works okay, I wasn’t paying like $500-$600 for a portable AC unit.

But if I can’t get the chiller before my next grow I’m just going to do coco, I am too a fan of that medium @Mark0427

That’s my other plant next to the DWC, it’s in a 4:1 mixture CoCo/Ocean Forest Fox Farms

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U can fill 20oz pop bottles or some 16.9 pz water bottles. Fill three quartes and freeze throw in non metlable cold cubes. Use bottles reg ice melts and changes the ph. Good luck

If you are running straight bucket hydro (DWC) you will be reducing the available volume by adding ice bottles, along with having to do this every couple of hours: no thanks!

I’m not sure if any of you guys were still following this or had interest.

But it looks like the temperature finally got to the roots. I got a pretty bad case of rot going on.

I’m probably just gonna call it on that gal.

My ocean forest/coco plant next to it is already getting orange hairs and I can see resiny trichomes forming. So I think that one should still make it.

It’s just way far behind what if’s growth should be at this stage.

My only worry is the rot spreading, but I don’t think it would if I pulled it out as fast as possible?

I just want to thank you all for the advice, especially @Myfriendis410

I’ll be taking all that to my best DWC and make sure it goes better lol.