RDWC how much PK to add

fartoblue

Well-Known Member
Hello all my first grow with RDWC system. So far my plants look great 3 weeks into flower 360 litre system 8 plants. I have another 8 plant system for veg.

I needed to veg the plants for a week longer in the flower room so started them on grow nutrients then just topped up with bloom nutes around 1 week into flower and have continued to do so, around 20 litres a day.

I am in the zero change out camp apart from flush (they had a fresh batch when they changed rooms from veg to flower).

My question is how do I add the additives such as PK and Shogun Dragon Force and the bloom booster?
Do I use enough to saturate the full system ie: 360 litres worth of PK in one go then just add the required amount to further top ups?
Totally new to RDWC so This may be a stupid question.
Many thanks
Blue
 

Renfro

Well-Known Member
So you run the same nutrients for the entire flowering cycle, just topping off with h2o?
 

fartoblue

Well-Known Member
So you run the same nutrients for the entire flowering cycle, just topping off with h2o?
No mate I top up with the appropriate strength of nutrient solution. I try and keep it in line with the Current Culture feed chart although I don't use their nutrients as they are bad to get hold of in the UK.
 

Renfro

Well-Known Member
Right on. As far as adding PK I try to watch my total PPM. I don't want that to run hot. With my nutes (GH Flora 3 Part) by the time I am adding PK I have stopped using the grow nute bottle to reduce nitrogen and thus I have more room in the PPM to add a PK boster or just more of the bloom bottle. Usually this equates to about 200 ppm of my total ppm of 1300 ish. I would like to see what other people do. I do use RO water FWIW.

Id imagine that in your setup you use RO to keep from building up the junk in the water.

Without dumping the reservoir Id probably make sure to limit adding nitrogen during flower and just let them eat a lot of whats in there. It will take some tuning to get where you wanna be. Lot of gues work as to whats in the res.

I used to run a flood and drain setup with a 200 gallon reservoir using lucas formula, I kept it topped off with RO water and only added back nutrients as required to maintain PPM. It did awesome.
 

fartoblue

Well-Known Member
Thanks for the advice Renfo. I use tap water but it is very soft with an ec of zero - 0.2 ec straight out of the tap 7.2ph ( I live in the sticks)

I let the nutrient level in the pots get low and added 50 litres of full strength pk with base nutrients to make it up to 1.4 ec (my water is 0.2 just now) added it slowly through the main storage tank ballcock feed. Think I will add the pk at full strength for a few days then drop to half recommended. I do have lots of air going in the pots.
 

5BY5LEC

Well-Known Member
PK and bloom boosters are the same thing. be careful. you'll lock out Ca and Mg if you add too much.

you should try nutes that don't need a PK boost as they have enough in their base mix.
This. Looking back, as soon as I hit it with the bloom nutes I saw Ca/Mg problems. When I backed off to a more 1:1:1 of the GH three part, those problems went away. Careful with that PK.
 
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