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View Full Version : question on topping off and reservoir changing



Dr. VanNostrin
12-09-2007, 02:24 PM
ok you're supposed to top off with half strength nutrients every day and change your reservoir every two weeks or so right? question: how often would i have to completely change a 14-gallon reservoir? still every two weeks? and by topping off with half strength nutrients, is it supposed to be half the strength of the current measured ppm, or half strength of what i am giving them? thanks for any help

Dr. VanNostrin
12-09-2007, 02:33 PM
oh yea its dwc my bad

rhizome
12-09-2007, 04:02 PM
If your EC has gone down, you top off w/ full nute- your plants are feeding more than transpiring.
If your EC has gone up, you top off w/ water until well below desired EC- otherwise you'll go high pretty quick- your plants are drinking more than they're eating.
You adjust the strength of your top-off solution to maintain a consistant EC in the res, or at least a manageable swing. Better to go low than high.

How often you change the res depends on the biomass/volume ratio. If you don't know what that means, do a full swap weekly.

Fertilizer is cheap compared to product- don't f%ck yourself over a couple bucks.

I've had rigs that would transpire 14 gallons a day- 14g is not very big at all.

the image reaper
12-09-2007, 05:17 PM
If your EC has gone down, you top off w/ full nute- your plants are feeding more than transpiring.
If your EC has gone up, you top off w/ water until well below desired EC- otherwise you'll go high pretty quick- your plants are drinking more than they're eating.
You adjust the strength of your top-off solution to maintain a consistant EC in the res, or at least a manageable swing. Better to go low than high.

How often you change the res depends on the biomass/volume ratio. If you don't know what that means, do a full swap weekly.

Fertilizer is cheap compared to product- don't f%ck yourself over a couple bucks.

I've had rigs that would transpire 14 gallons a day- 14g is not very big at all.

thanks for this, now it makes sense to me :thumbsup: ...