DWC Noob questions - First grow

[KingJames]

I'm in the middle of researching/buying everything I need for a DWC setup and just have some questions for things that are taking up lots of internet time researching.

1) How often do I need to change my reservoir water, assuming everything is going okay? (I know this is a topic of much debate)
2) How do I actually fill/change it? I have 2x84ltr(22 US Gallons) reservoirs (thought of using an auto siphon to empty and attaching a hosepipe to my shower hose) Because of electrics, I don't want to be carrying heavy water filled reservoirs in and out of my tent
3) Am I right in thinking that I would need to fill them up to about 16 US gallons? (around 3/4 of the res)
4) Is there any scientific evidence on what the best nutrients are to use? There's too much choice and too many opinions online. This suggests that there is no consensus, but I just want to be sure!
5) By my calculations, using Flora Duo in 16 gallons of water, I'd need about 2L of A and 4 litres of B - does this sound about right? That seems like an awful lot for one grow cycle, but it also seems correct.
6) Is 4 circulation fans overkill? I'm thinking of having 1 under the canopy, 2 blowing over the top and 1 more blowing towards the lights.

 

[Nate_in_AK]

Hello and welcome to the Farm!
I'm only on my 2nd DWC grow, so take my feedback with a grain or fifty of salt.

How many plants are you hoping to raise at a time on this system?
Are you looking into RDWC with top drip? Your described environment sounds ideal for this, I think.

On my 5 gal buckets I have an extra empty bucket that I use when I need to change the res water. I lift the lid with plants off the base and onto the empty bucket, then drag the original bucket out for rinse and refill. With 16 gal, you're looking at significantly more weight per tub. I good transfer pump might work, but you may also be just as well off bailing the big tubs out with smaller buckets... Just spit-balling.

I don't know about any controlled experiments that compare nutrient qualities, if that's what you're asking. It is just about universally accepted that all the vendors suggest far too strong a mix, and you should start out much lower strength than recommended.

Circulation fans should not blow directly on your plants, or induce tropical storm force winds.

A few things you didn't touch on that I'll offer unsolicited advice on because it's free:

• Anti-Fungal additives? Southern AG, Hydroguard, etc. You need this. Need.
• Also needed: pH meter with calibration formula, and a TDS meter for PPM readings.
• Patience. So much patience.
• Did I mention patience?

I wish you luck! Don't be hesitant to post more questions, and please come back and share pictures and do a grow diary once you get underway.

 

[KingJames]

Thanks mate, some great advice.

My system is just standard DWC for now with airstones etc. I plan on running 2 plants per reservoir so 4 in total.

Re anti-fungal, yes hydroguard is on my list and I have a pH meter and a TDS/EC meter.

I think I'm just going to use a submersible water pump. If all goes well, I might only be fully changing water out every 20 days or so (once I've topped up the equivalent of my initial fill).

 

[GreatWhiteShart]

1) How often do I need to change my reservoir water, assuming everything is going okay?
I do every 7 days fully empty and sanitized with a chlorine and dawn soap dilution. I will prob not go over 10 days, but my rez Temps are 70-75 degrees. That's the heart of the temperature danger zone for bacteria growth. Better safe than sorry

2) How do I actually fill/change it? I have 2x84ltr(22 US Gallons) reservoirs
Use a small aquarium pump
What ever you do make it easy because the harder you make it, the more you will not do it lol.

3) Am I right in thinking that I would need to fill them up to about 16 US gallons?
I use 6 gallons per plant until they start strech then I bump it up to 9 gallons.

4) Is there any scientific evidence on what the best nutrients are to use?
Use nothing organic.......
I use silicate, cal mag, base nutrients. Anything else is up to you
General hydroponics is quality stuff
I use maxi grow and bloom

5) By my calculations, using Flora Duo in 16 gallons of water, I'd need about 2L of A and 4 litres of B -
no idea, hydro is much more expensive then soil lol

6) Is 4 circulation fans overkill? A good vent fan and two small circulation fans usually does itfor a small tent.

Good luck man, hydro is so much easier as long as you don't go cheap and just be methodical about sanitation and watching your ec and ph!

 

[Nate_in_AK]

My system is just standard DWC for now with airstones

You've likely already got this under control as well, but just in case: Make sure you are pumping enough air with decent stone surface area:

In most cases, an air pump should move about 500 cubic centimeters (0.5 liters) per minute of air for each gallon of water. This is a good range for most home hydroponic systems. (stolen from some internet article)

 

[GreatWhiteShart]

Overkill with air stones ...........
Cant have too much air

 

[KingJames]

Thanks for the responses guys. I've heard a bit about Maxi Bloom and I assume Cal Mag and Potsil are standard? As additional nutes, what do people think about Beastie Bloomz for the flowering stage?

 

[GreatWhiteShart]

Maxi series is economical and honestly I use it with great results, never have to re-ph my rez once it fully disolves.
Other stuff
Armor si
Humic acid
Some sweetener (flora nectar)
I never had any luck with beastie bloom, I switched to kool bloom

I used fox farm for years in soil its great
But for hydro I switched to general hydroponic.

Cheers

 

[KingJames]

I bought Maxibloom. Heard/read good things about it.