How often should I change out my dwc res.?

[Nortin]

Im just starting out with hydro, built my tub and almost ready to fire it up. Im going to use the lucas fomula and do water change outs since I do not own a ec meter yet. How often should I change my res water / nute solution?
The local hydro shop guy said once a week but he also sells nutes too so I think his opinion might be influenced by greed.
Thanks!

 

[FreezerBoy]

No meter, do whatever Lucas says. With a meter, I can go for months.

 

[medi-useA]

Trial and error is the norm in these situations...
You can assess everything address everything and still have things go pearshaped...

Start with recommended formula and res change-outs..observe you plant and tinker...it might do just as well or better on half or three quarter strength nutes!?...some are also heavy feeders.

You might get away with topping up the res every second time...

Start as recommended and then ....tinker

muA

 

[Craven_au]

every 2 or 3 week would be ok just keep an eye on the PH daily keep it below 6 and above 5

 

[Ganoderma]

there can be several items that can affect how often or how long youcan go between changes.

1. The size of your Res or dwc containers

2. Your water sorce, RO water or tap water use can have an affect

 

[slowandeasy]

Depends on alot of variables. I have been just topping off the past few runs and keeping the level stable. Works great, if you monitor everything daily. What nutes you using? I can tell you that if you use Maxi-Bloom or FNB they are very potent and a total change out requires premixing your nutes a day in advance so they can be fully dissolved and not screw up your roots/plants. DWC is awesome, but you will see changes Very fast...like overnight if things go wrong. Good luck