flood and drain tables...

[cjk]

i've been thinking of possibly settin up a flood and drain system and i had a few questions...
1. with flood and drain tables, is water temps not as big of an issue? i don't want to have to run a chiller and my room stays pretty cool.
2. i'm going to either do coco/perlite or clay pebbles. any opinions to sway me one way or the other? positives or negatives of each? obviously with the pebbles i'd probably be flooding more often which i like ...
3. uhhhhhh, damn i just forgot what i was talking about, that's all for now, haha...

 

[stinky33]

rez temps will remain a little lower than your ambient room temp, because you are not constantly running the pump and heating up the water.
i recommend an air stone in the rez,
coco/perlite works well with a 15 min on every 3 hours for me. you can go more frequently or less and still have great results.
the bigger your rez the more "unattended" you can leave it once you have it set up correctly, but this also uses more nutes for each rez change.
lastly, you can choose to run a "dead" rez if you think your rez temps will be too high, thus minimizing/eliminating any potential for root rot. just add sm90 or bleach at recommended levels in your rez. search here and you will find lots of references.

good luck!

 

[smokingjoe_]

You could use glass marbles in a pot on a flood drain table and it wouldn't matter. I personally prefer to fill the whole table with expanded clay balls. Huge root balls are always good.

 

[Marshall]

water temps are not a big issue.

I have run a lot of tables in hydroton. I have done pots, and just filled the table. I prefer the pots.

I have never run coco 100%. But I did put some clones in coco, then in my table and I had coco particles all over. Didn't harm anything, just messy.

 

[cjk]

thx guys! are res changes really necessary so often. it seems that as water is used up or evaporated, adding fresh water to top off would ultimately change the res out. now how long a complete turnover takes, idk ...

 

[growshopfrank]

thx guys! are res changes really necessary so often. it seems that as water is used up or evaporated, adding fresh water to top off would ultimately change the res out. now how long a complete turnover takes, idk ...

Unless you are doing some lucas formula plan the usual rule of thumb is to do a res change when you have added one half the res volume as make up eg. with a fifty gallon res when you have added twenty five gallons of make up. Myself I use tap water (less than 120 ppm) for the first fill than RO water for make up.

 

[Phaeton]

I try to change my res weekly, quite often it is two weeks, occasionally it it three. The tds readings start climbing faster and faster with time.

As cjk asks, why does adding water and/or nutrient not keep the system self-replentishing? I know it goes bad, but why?

Thank You.

 

[ijim]

A friend was using 2000 watts over a 4'x8' table and was having temp problems at veg. when the lights were close. He installed a solenoid gate on his drain and let the water free fall about 12" into the reservoir. This aerated the water plus cooled it some. Then he got silica rocks from the garden center and surrounded his pots with them. Kept temps nice and cool and increased his root mass, yield and resistance to critters and disease with the silica.

 

[growshopfrank]

I try to change my res weekly, quite often it is two weeks, occasionally it it three. The tds readings start climbing faster and faster with time.

As cjk asks, why does adding water and/or nutrient not keep the system self-replentishing? I know it goes bad, but why?

Thank You.

One common theory is that plant food is made up of many different ingredients and plants use varying amounts of these ingredients (that change in different stages of growth) and that eventually leads to an imbalance of the solution
and for an opposing theory here is a read on the Lucas formula
http://www.cannabis-world.org/cw/showthread.php?t=892