Reservoir Maintenance (Hydro)

I've looked around the forums and could not find anything. My Question is how often do you change the water out of the reservoir. I am not yet set up and just looking for info before I do (Never done this). I will have a 20gal. res and about 5-6gal. in it. Set up with air bubblers/pumps/and nutes. I will have one for Veg/clones/and flower. Any help is greatly appreciated. Thanks!

its tell you on the nute bottles
but in genneral it every 2wks
but ive herd of people going no change with dwc
but you have to keep the water leveled and ph'd

Thanks for your time! Thats great info. Thanks again!

My res change schedule is as follows:
Clones - once per cycle (just water, no nutes)
Vegetative - every 14 days
Flowering - every 7 days

That works well for me.

gcvt420: Thanks!! Nice info.

A good rule of thumb is 1/2 the volume top off or 2 weeks. Which ever is first. So just say ur res is 20 gal. Water will become low as they drink it and it evaporates and such so u have to top it off to regulate ur ppm. ur plants use more water then nutes so if ur 20gal was at say 1000ppm and they used 2gals of the water, then ur ppm will be higher now and could become toxic causing nute burn. So u top it off with 2gals of plain water and ph the tub. Keep track of how much u top it off. Once uve topped it off with 1/2 the volume(in this example 10gals as ur original res is 20 gal) then its time for a change. So 2 weeks or 1/2 ur res top off. What ever comes first

I dont change it unless something is wrong. I top off the water level and adjust the ppm and check the ph. Adjust if needed, but its not often the ph is off at all.
i even went out of town for longer than I expected and when I got home I found the plants had like 1/2" of water in the res. Its normally like 15". So I filled it back up added nutes and everything was fine.

I think its kind of a waste to change it because your dumping nutes down the drain. But heres the rub. Plants use different parts of the ferts at different rates. So I can see that its possible to get it wrong. I could see one compound being used more and others not as much. So one part is now lower than ideal. So your ppm pen says add sone food. You do and now the compound that was low is fixed but what about the others? Would they now be at such a high level as to be toxic? Could be. So its up to you as the grower to be it tune with the plants and what they need. A full change may be a waste or it may be just the thing your plans are waiting for.....

gcvt420 said:

My res change schedule is as follows:
Clones - once per cycle (just water, no nutes)
Vegetative - every 14 days
Flowering - every 7 days

That works well for me.

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I agree with this, and I don't add nutes mid week in flower. In fact, I never even check ppm anymore.

I too don't check Ppm anymore. My plants tell me if sumthings needed or has too much and in DWC its fast and ez to correct. Even tho I gave u my rule of thumb doesn't mean I practice it. I have a 3week perpetual system so every 3 weeks when I harvest and replace, I do the nute change as well. I have 1 question tho, y r u ony gonna have 5-6 gals of soup in ur 20 gal tubs? U sure the water level is gonna be high enuff? And last long enuff? That's the downside with DWC, lots of nutes and water needed for so little plants. Like I mean 20gal res will feed a 4x4 table of say 30 plants where as DWC u can really only cram 6-8 depending on size. The water volume to surface area doesn't add up but still a great cheep system

Resinraider: Thanks first off. I hear you on the volume thing. I got that # from the greenguy video for the space Im using. Will do a "ghost" run first with out plants for a day or two and see were my exact #s need to be to run my DIY system i.e. lights on timers h20 loss due to evap little things like that, as I am very meticulous. Then I am doing an actual grow run with some seeds I have from last july, and dont care much for, but would still like a decent crop (NL/ with something). Then I will be ordering the real deals and hopefully with all my data from the ghost runs, that will help the CHEESE i want to grow. Also my trays are 2'Lx2'8"W and 8"H. 2 in the veg and 1 in the flower. Any advice, critisism, fowl mouthing, props, pos/neg feedback, & +reps are appreciated the more info/data I get the better the sweet sweet chiba!! THanks all! (Illegal smile & doctorD) Great info.