Water left in RDWC system between Rez changes

hydroponicronic · Sep 6, 2020

Hey all!

First time poster but been lurking for a while now This is an excellent forum with tons of great info! Thanks for that!

Almost ready for first run in a 4 bucket (8 gallons each) system. The 5th 8 gallon bucket is the rez outside the 4x4 tent. The total water volume will be around 33 gallons to start.

My concern is when draining the system for Rez changes, there is approx 4 gallons total left in the system that is not easily removable due to the 2” bulkheads having to be positioned slightly above the very bottom of the buckets. Basically a gallon per bucket inside the tent will be left. The Rez can be vacuumed out with minimal effort.

I will be mixing nutes in a separate mix barrel before pumping them over to the Rez. My vision was when it is time to up the ppm’s I may have to mix slightly stronger due to the weaker solution being trapped in the system. That wouldn’t be too bad. I’m horrified thinking if I run in to any kind of more serious problem like rot or something that not having the ability to completely drain the system will quickly become a huge PITA!

Do you guys think this is a concern? I’ve been thinking about a bottom drain system however the babies are about a week away from go time and I was going to run as is for the first grow.

Thanks for the input!

MHOGSMI · Sep 10, 2020

You should be fine. You could always empty your system as much as possible, fill it 1/4 way up, then empty again. To dilute what was left behind the first time. I'm running about 75 gallons and I always have 8-10gallons that never make it out. I don't think it's hurting my grow at all. Cheers though.

hydroponicronic · Sep 10, 2020

Thanks for the reply @MHOGSMI ! That makes me feel better! The dilution idea is something I never thought of.
Your crop doesn't seem to be suffering that is for sure!
Appreciate it man!

Aqua Man · Sep 11, 2020

No issue I only do 50% water changes... I have my reasons and not advocating you do this. The important part will be deciding if you are going to run sterile or live and do either properly so you don't run into issues to start with. Also following a proper water change program will make sure your ratios stay balanced. The only thing you may want to keep an eye on is any precipitate you see and if its building up

hydroponicronic · Sep 11, 2020

Thanks @Aqua Man!
The plan is to run sterile for the first couple grows with weekly rez changes.
Thanks for the input!

Mospeada · Sep 11, 2020

I think while you're learning exactly what your plants eat, it would be good to get rid of it. More so to have consistency with your tds/ppm. It's hard to determine what the plants are eating if you leave the left overs in the res. I just pump out what I can and use a wet dry vac to suck out the rest. Eventually you'll see what they need and won't have to change your res as often. I went from changing weekly to no changes at all on my current grow.

Aqua Man · Sep 11, 2020

hydroponicronic said:
Thanks @Aqua Man!
The plan is to run sterile for the first couple grows with weekly rez changes.
Thanks for the input!

A few quick tips for a first timer.

Change the nutrient solution no less than once you add back the volume of you system.

If using peroxide use 30-35% food grade hydrogen peroxide and apply every 3 days. Making sure to dilute it before adding to the res.

Make sure your source water is adequate in ppm and alkalinity.

Record tour test results daily as they will help as early indicaters to issues.

hydroponicronic · Sep 11, 2020

Mospeada said:
I think while you're learning exactly what your plants eat, it would be good to get rid of it. More so to have consistency with your tds/ppm. It's hard to determine what the plants are eating if you leave the left overs in the res. I just pump out what I can and use a wet dry vac to suck out the rest. Eventually you'll see what they need and won't have to change your res as often. I went from changing weekly to no changes at all on my current grow.

Thanks @Mospeada. I agree while learning the ins and outs it would be beneficial to have the ability to track everything exactly.
I should be able to vacuum out the front two buckets during the grow without too much hassle. That would leave about 2 gallons trapped in the other two buckets which is better than 4 I guess. Unfortunately, I only have access to the front of the tent due to where it sits in the laundry room. Accessing the lids of the back two buckets during the grow won't be possible once the scrog is in place.

Aqua Man said:
A few quick tips for a first timer.
Change the nutrient solution no less than once you add back the volume of you system.
If using peroxide use 30-35% food grade hydrogen peroxide and apply every 3 days. Making sure to dilute it before adding to the res.
Make sure your source water is adequate in ppm and alkalinity.
Record tour test results daily as they will help as early indicators to issues.

Thanks @Aqua Man. I think I am all set in that regard. RO water, spreadsheets, 35% Hydrogen Peroxide, BlueLab Guardian with wifi on the rez, etc. I have read countless Hydro threads while choosing what kind of system i wanted to build and countless more figuring how to run it properly.
I have grown using flood and drain many moons ago so I do have some experience. There is so much information out there now that there is internet and forums like these! Now that it is legal in Canada, the hydro store doesn't seem to be as much of a "covert operation" as it was years ago. HAHA!

I appreciate all the feedback!

Aqua Man · Sep 11, 2020

hydroponicronic said:
Thanks @Mospeada. I agree while learning the ins and outs it would be beneficial to have the ability to track everything exactly.
I should be able to vacuum out the front two buckets during the grow without too much hassle. That would leave about 2 gallons trapped in the other two buckets which is better than 4 I guess. Unfortunately, I only have access to the front of the tent due to where it sits in the laundry room. Accessing the lids of the back two buckets during the grow won't be possible once the scrog is in place.

Thanks @Aqua Man. I think I am all set in that regard. RO water, spreadsheets, 35% Hydrogen Peroxide, BlueLab Guardian with wifi on the rez, etc. I have read countless Hydro threads while choosing what kind of system i wanted to build and countless more figuring how to run it properly.
I have grown using flood and drain many moons ago so I do have some experience. There is so much information out there now that there is internet and forums like these! Now that it is legal in Canada, the hydro store doesn't seem to be as much of a "covert operation" as it was years ago. HAHA!

I appreciate all the feedback!

Sounds like your good to go. Just make sure your adding back cal mag, micros and adequate alkalinity when using RO if your nutrients aren't designed to.

hydroponicronic · Oct 26, 2020

Here's a quick update. So far so good with the 1st grow.
Vegged for almost 5 weeks with 2 toppings and lots of training.
Currently day 11 of flower.

Cannafollow · Oct 26, 2020

hydroponicronic said:
Here's a quick update. So far so good with the 1st grow.
Vegged for almost 5 weeks with 2 toppings and lots of training.
Currently day 11 of flower.View attachment 1048595 View attachment 1048596

That is looking amazing! Great work

Aqua Man · Oct 26, 2020

Yup looking very nice

Water left in RDWC system between Rez changes

Water left in RDWC system between Rez changes

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