Want to Transition into Sterile Hydroponics. Flood and Drain. Need Guidance.

So Ive always used beneficial bacteria in my hydro flood and drain setup these past few years. But I want to keep costs as low as possible. I use Great White/Mykos WP/Hydroguard and they work well but the cost gets up there real quick with all the 70gal reservoirs I have.

Ive used h2o2 in the past but pouring it in my rez every 2 days is too much work for me honestly. I want something thatll do the job for a week til the next dose.

Ive read about pool shock on these forums and bleach and all that stuff.

Can anybody guide me on which product to use thatll require the least amount of continuous dosing into rez? I dont have time to pour in h2o2 every 2 days into all my reservoirs. Need something thats hands off as much as possible.

if you only want to dose 1x/week, i think a max dose (5ppm) of free chlorine via HTH pool shock is your best and by far cheapest option. if my math is correct, 3.5 grams per 70 gal is 5 ppm.

When I did flood and drain in containers of hydroton I just used Clorox bleach "sodium hypochlorite" in the reservoir. Pool shock is calcium hypochlorite. There isn't enough sodium or calcium in either to have any effect on the plants but the small amount of chlorine provided by either will help prevent any nasties from growing in your reservoir.

rkymtnman said:

if you only want to dose 1x/week, i think a max dose (5ppm) of free chlorine via HTH pool shock is your best and by far cheapest option. if my math is correct, 3.5 grams per 70 gal is 5 ppm.

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Gotcha. When I was researching about sterile hydro. I remember seeing you advocating pool shock back then.

You use GFF now right? What made you switch from sterile?

xtsho said:

When I did flood and drain in containers of hydroton I just used Clorox bleach "sodium hypochlorite" in the reservoir. Pool shock is calcium hypochlorite. There isn't enough sodium or calcium in either to have any effect on the plants but the small amount of chlorine provided by either will help prevent any nasties from growing in your reservoir.

How to operate a sterile hydroponic system

FAQ --------------------------------------------------------------------------------------------------------------------------------------------- Whats the best sterilizing agent for a hydroponics reservoir? There are many ways to have a sterile reservoir, chlorine, H2O2, Ozone, etc. All have...

www.rollitup.org

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I see. How often is bleach required to top off with per week? and how much would I need to use for a 70 gal rez?

newbplantgrower420 said:

I see. How often is bleach required to top off with per week? and how much would I need to use for a 70 gal rez?

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A 70 gallon reservoir would require about .6 oz to be at 4 ppm's. Since chlorine dissipates it would need to be added every 3 - 4 days.


Your Solution
To make your chlorine solution add 0.63 fluid ounces (US) of bleach to 70.00 US gallons of water
Dilution of bleach to water ratio is1:14,285
Assumptions
Assuming 6.00% sodium hypochlorite is used, this is equivalent to 5.80% available chlorine. Available chlorine is the amount of chlorine available for disinfection.
1 drop ≈ 0.05 ml
1 teaspoon ≈ 5ml
1 tablespoon ≈ 15 ml
1 cup ≈ 250 ml

This calculator allows you to find the ratio's in both US and metric measurements.

You can greatly reduce the need for adding chlorine, etc by doing two things.

1) Do not use or add anything even remotely related to anything organic. Use pure salt based nutes and addons only.

2) keep the rez temps low at all times. Preferably below 70F.

Prior to making those changes I was constantly fighting bacterial growths in the rez and root rot. After I made those two changes, I now only add aprox 2PPM chlorine (pool shock) when I first fill the rez, then dont need any more until the next fill - aprox 7 to 8 days later.

Oh - minor but very important detail - I run DTW, so I have it much easier than most doing any kind of hydro. You wont be able to do Drain To Waste with F/D, but you can still have a much happier rez by making those changes.

newbplantgrower420 said:

You use GFF now right? What made you switch from sterile?

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correct, i do use GFF now. no particular reason for switching. each way works very well.

Larry3215 said:

You can greatly reduce the need for adding chlorine, etc by doing two things.

1) Do not use or add anything even remotely related to anything organic. Use pure salt based nutes and addons only.

2) keep the rez temps low at all times. Preferably below 70F.

Prior to making those changes I was constantly fighting bacterial growths in the rez and root rot. After I made those two changes, I now only add aprox 2PPM chlorine (pool shock) when I first fill the rez, then dont need any more until the next fill - aprox 7 to 8 days later.

Oh - minor but very important detail - I run DTW, so I have it much easier than most doing any kind of hydro. You wont be able to do Drain To Waste with F/D, but you can still have a much happier rez by making those changes.

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I have a bit of a problem in my LED rm. I keep temps at ~80F with my mini split so naturally the rez is higher than Id like at ~75Fish. So i cant really change this factor....even if I wanted a chiller I have no space at all.

Never used organics. Only salts.

rkymtnman said:

correct, i do use GFF now. no particular reason for switching. each way works very well.

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how much mL would I have to use of GFF for a 70gal rez?

Just a heads up. Pool shock/chlorine lasts a couple minutes in a hydro environment. Not a week like you're looking for. I've played around with it and i didn't find it reacted with a nutrient mix of Epsom salts and Maxibloom using orthotolidine But when cycled through the roots and perlite medium. The plants seemed to eat it. After cycling, no chlorine smell and all tests show zero free or available Cl.

I'm not saying it doesn't work but it's like a short lived kick.

Bit of decent info here: https://manicbotanix.com/disinfection-in-hydroponics-root-disease-prevention/

ubluntu said:

Just a heads up. Pool shock/chlorine lasts a couple minutes in a hydro environment. Not a week like you're looking for. I've played around with it and i didn't find it reacted with a nutrient mix of Epsom salts and Maxibloom using orthotolidine But when cycled through the roots and perlite medium. The plants seemed to eat it. After cycling, no chlorine smell and all tests show zero free or available Cl.

I'm not saying it doesn't work but it's like a short lived kick.

Bit of decent info here: https://manicbotanix.com/disinfection-in-hydroponics-root-disease-prevention/

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what would you recommend for something cheap and dose every week?

Not sure. I plan on trying enzymes and bennies but like you said, they can be pricey.

3ml/gal of 29% H2O2 every few days is what I do. It doesn't get any easier than this ..but then again my rez is only one gallon.

I bought a $10 container of pool shock and used it for 6ish years and never finished it before I moved and threw it out because the lid was cracked.

It worked awesome a tiny amount went a long way. I dosed the res about every 3-4 days(whenever I remembered lol) and never had res problems again after I started using it. I ran flood and drain for 10 years on a perpetual cycle until I moved across country last fall.

newbplantgrower420 said:

how much mL would I have to use of GFF for a 70gal rez?

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7mL give or take

ubluntu said:

Pool shock/chlorine lasts a couple minutes in a hydro environment.

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minutes? at what ppm of free chlorine were you dosing?

rkymtnman said:

minutes? at what ppm of free chlorine were you dosing?

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High doses sometimes. Around 3ppm usually.. The stock solution I made is a lot stronger than what I've seen others use. I believe it's 4.7grams of 65% HTH in 500ml. Used up to 1tsp per gallon a couple times for testing.. sometimes consecutively after cycling, testing without any noticeable effect to the plants. 1ml per gallon of fresh water shows a strong "good" on HTH test strips. It tests much stronger than UC Roots.

The link I posed says 2minutes but It seems stable in the solution but disappears after a single cycle. I don't believe it's reacting with the nute mix like some say. Not sure if it dissipates when pushed through a dripper,, the plants eat it, or it's just doing what it's suppose to and getting all used up? Would be interesting to compare it in DWC with the roots directly exposed.