new diy rdwc build can i get some advice

hello everyone im building rdwc system but there are some things im unsure about and im hoping you pro's can help out

how many and what size tubs should i be looking at to go under a 600w light? i grow in grow tents size is 2.4mtr square so there will be 4x 600w in there,
now im unsure whether to go for 4 under each light in something like 25ltr/50ltr 6/13gal tubs or 2 under each light in 80ltr/21gal tubs, i obviously want to fill my space but will 4 under each light be too crowded?

say ive got 6 plants in 6 gal tubs and an extra 6 gal tub used as the reservoir, i understand the res is used to keep the circulation going but if the PH or EC needs adjusting dont i need to empty all the water out of the system into a big tank, adjust ph/ec then refill the system?
If i did this straight into the res tank wouldn't there be a ph/ec spike while the system mixes?

im sure ive got more questions but i'll make this the last for now i dont want to bombard you too much!
do i only need a water heater in the res tank i dont need one in every tub?

Im not a total noob ive been growing for about 5 years mainly in coco but have grown in mud as well, ive been looking at these systems for a little while now and it never ceases to amaze me on the results i see you guys get,,,,,gonna be up n running in 3 weeks

Dump your shit into the res. There's no shock unless you use way too much of something. Keep it simple. Water heaters? You mean a chiller?

Will you be using a SCROG? Sea of green method? LST? FIM / topping?

I encourage the idea of rdwc with built-in screens attached to each tub-lid. Ensures that you will use all the square footage and doubles as supports for heavy flowering strains. You also need to consider how many gallons you will be dealing with. I had great success with x4 27gal HDX home depot totes attached to a 3gal tidy cat plastic litter box. No joke works flawlessly unless heat is an issue than water cooling was my only issue.

If you wanted to take a look at how frustrating design work can be =) link below is my 1st built rdwc.
http://rollitup.org/t/the-vumar-grow-rdwc.858399/

GIJonas said:

Dump your shit into the res. There's no shock unless you use way too much of something. Keep it simple. Water heaters? You mean a chiller?

Click to expand...

thanks Jonas so people tend to dump straight into the active res thats cool makes life a bit easier
yes i will probably need a water heater for lights off period, my res tank will be kept outside the tent and inside the tent at the moment with lights on im looking at a fairly steady 24c/75f, with the temperature starting to get cooler now in the UK i will be surprised if i need a chiller within the next 4 months or so.

Hi Vumar i will be trying scrog and lst i dont have great experience in either ive always topped and kidda pruned, badly probably its something ive been intending to read up on,
in what kind of space and how many lights did you have the 4x 27 gal totes under i prob going to find out for myself im just about to look at your thread, are you in the UK Vumar?

I'm not UK, sorry friend.

yeah i got that from your thread mate i saw you mention the attitude seed shop we got one in the UK,

are you still running your rdwc system then it looked like you were trying to get into soil? what kind of crop were you getting from your rdwc system?

I found in Alaska growing indoors in winter I needed small cheap aquarium heaters to keep res temps up! But a window cracked because of lamp heat. Go figure.

^Is the ground insulated?

squidgy pete said:

yeah i got that from your thread mate i saw you mention the attitude seed shop we got one in the UK,

are you still running your rdwc system then it looked like you were trying to get into soil? what kind of crop were you getting from your rdwc system?

Click to expand...

I swung out with that specific rdwc but the design itself is very solid. I ended up fracturing my skull and suffering a brain bleed while I was at my day job... so since I got injuried... I got fired. Spent 8 days in the hospital. So I didn't have the time or cash to put into the rdwc/chiller issue(s). The TLO soil is strictly for fun and I usually fire up a couple soil buckets when summer rolls in and heat becomes more of an issue. Those soils were more so to fill up the Sq footage I was illuminating and missing with the hydro buckets. The plants also provided additional shade for the totes n hoses.

hotrodharley said:

I found in Alaska growing indoors in winter I needed small cheap aquarium heaters to keep res temps up! But a window cracked because of lamp heat. Go figure.

Click to expand...

Often this happens due to evaporation from the res, especially if there's a fan blowing air across the water's surface. Covering the res should help.

I disagree. That's clearly a thermal crack. Bulb heat vs Alaskan winter.

Bulkhead fittings. Do NOT use uniseals!


I use these to fit to 1" hoses that go between runs and to the control bucket.

Vumar said:

I disagree. That's clearly a thermal crack. Bulb heat vs Alaskan winter.

Click to expand...

I was talking about temperature drop in the res, not the lamp lol

hotrodharley said:

I found in Alaska growing indoors in winter I needed small cheap aquarium heaters to keep res temps up! But a window cracked because of lamp heat. Go figure.

Click to expand...

small water heaters needed for growing in Alaska in the winter! i may need a water chiller after all

firsttimeARE said:

^Is the ground insulated?

Click to expand...

well its on second floor timber flooring with carpet so yeah i would say so mate

Vumar said:

I swung out with that specific rdwc but the design itself is very solid. I ended up fracturing my skull and suffering a brain bleed while I was at my day job... so since I got injuried... I got fired. Spent 8 days in the hospital. So I didn't have the time or cash to put into the rdwc/chiller issue(s). The TLO soil is strictly for fun and I usually fire up a couple soil buckets when summer rolls in and heat becomes more of an issue. Those soils were more so to fill up the Sq footage I was illuminating and missing with the hydro buckets. The plants also provided additional shade for the totes n hoses.

Click to expand...

sacked for fracturing your scull at work wow that really is shit! hope you get some compo out of it mate, your head sorted now?

im building one out now...i could take some pictures...if ttystikk lets me share his design.

well its already built...but since im waiting on a chiller its not functional so I could take pictures of it

firsttimeARE said:

im building one out now...i could take some pictures...if ttystikk lets me share his design.

well its already built...but since im waiting on a chiller its not functional so I could take pictures of it

Click to expand...

that would be much appreciated the more info i can gather now will hopefully save me time money and fuck ups later

Don't be surprised if you do need a chiller in summer. I had to run one. But not often considering. Temps in Central Alaska can hit 100. And do. But thank goodness not often.

hotrodharley said:

Don't be surprised if you do need a chiller in summer. I had to run one. But not often considering. Temps in Central Alaska can hit 100. And do. But thank goodness not often.

Click to expand...

i might just stick a bucket of water in my grow room now and see what temps i get, i think it will give me an idea of how warm the water will get, im still hoping i will manage without for the next few months

im thinking of fluming rather than air stones, if ive got an 8 x 30lt bucket system i want to flume into 6 of those at the back then the water from them will pass through the last 2 buckets at the front,
what size water pump do i need to be looking at?

also how does the water pump for the chiller fit in? should i be pumping in from one of the grow buckets and out into the control tank or just in and out of the control tank? what size do i need for that?

ttystikk said:

I was talking about temperature drop in the res, not the lamp lol

Click to expand...

I would hope so lol. Whats this design youve shared with firsttime??