Flushing hydro plants

[Surfer Joe]

I have a plant in a 20L bubble bucket that holds 14L of nute solution below the mesh pot and is ready to harvest.
It drinks about 3.5 to 4 L per day now, but how do you flush a hydro plant?
Just filling the bucket with plain water once means that the plant will drink it up in about 3-4 days, but is that the same as flushing?
Should I use a flushing agent such as canna flush in the plain water?

 

[FilthyFletch]

You can use plain water for the last week of the plant but using a flushing agent like FloraSheild or other brand helps draw out nutrient salts and build up better.

 

[churchhaze]

The difference between a flushing agent and plain water is that the flushing agent uses sugar to keep the osmotic low high so water doesn't surge into the plant suddenly. Whether this make a difference, i dunno.

 

[FilthyFletch]

Basically they do the same the idea is to stop nutients from being taken in and just clean water. The flsuhing solution helps break down the salts faster. I like to flush 7-10 days at end of hydro cycles. I run FloraKleen and use it with pure water. I change the res in 3-4 days and repeat.

 

[Surfer Joe]

Thanks everyone, that's very helpful.
My tap water is pH 7.7, so I have to use pH down to get it to the desired 5.8 range, but doesn't that then add phosphorus or nitrogen back into the water?
If there are no nutes in the water at the end anyway, will it matter if the water pH is high since that causes nute lockout and there are no nutes to lock out?
Or will the high pH hurt the plant in some other way?

 

[churchhaze]

You should use the phosphoric acid based pH down. A high phosphate level at harvest actually increases burn quality because high phosphate is a signal to inhibit an enzyme called AGPase which converts sugar to starch.

Inhibiting AGPase means less photosynthetic flux is converted into starch (starch is bad in final product).



Red variables inhibit AGPase while blue promotes it. Pi is inorganic phosphate.

Thanks everyone, that's very helpful.
My tap water is pH 7.7, so I have to use pH down to get it to the desired 5.8 range, but doesn't that then add phosphorus or nitrogen back into the water?
If there are no nutes in the water at the end anyway, will it matter if the water pH is high since that causes nute lockout and there are no nutes to lock out?
Or will the high pH hurt the plant in some other way?