Grow Mediums Flushing a hydro plant

[Surfer Joe]

I'd buy some RO or Distilled water for the flush, I'm going to move my netpot to a 5 gallon bucket and use distilled water. With the rootball most people have your only going to be able to put maybe 3 gallons in at one time, so it would be worth the price if you use 12 gallons or so of distilled water.

You're right, my 20L bucket only holds about 14L under the net pot so investing in 10-12 gallons of distilled water is not too much if it will help them finish off better.

 

[Pal23]

Lol...You're the expert. Would the sudden change of pH of the plain water shock the plant or does pH only affect nute lockouts/uptake?
Would using something like lemon juice to lower the pH be a better option?

A higher PH than usual whilst flushing her won't stress her or shock her, bare in mind you try to avoid stressing/shocking them whilst growing to avoid stunting the plant's potential. By the flushing stage she has already reach her full size so even if she did get a bit stressed nothing will happen. Having just water in the res without nutes is the important part as it will force the plant to cannibalise it's leaves and then they will yellow and die. Keeping her in the correct PH range is essential whilst growing for the uptake or nutrients but imo really not necessary for a flush! If not lowering the PH will play on your mind and cause YOU stress then go ahead and use lemon juice or a ph down/cleansing agent for peace of mind but just know that many of us simply use tap water alone with great success. I know I commented something similar yesterday but the debate still seems to be going on so thought I'd give my "My 2 cents" :Sharing One:

 

[Surfer Joe]

Thanks. I just tested some tap water that I passed through a Brita filter and it lowered the pH from 7.7 to 6.3 and reduced the EC from 0.7 to 0.4 and the ppms from 375 to 200, so I think that I will use just that since you guys don't report any problems with flushing water being a higher pH than nutes.
I already have the canna flush for the soil plant, so I will add that to the hydro flush water as well.
Thanks a lot for all of the informative replies to everyone.

Here is a shot of the plant two days ago at flower day 57.
It is on the reduced nutes until the next bucket change and then I may start to flush or do the canna guide final week suggestion to use just cannazym and canna boost, which supposedly don't add any ec or ppms to the water.
The trichs are currently about 70% milky with the rest clear and only a couple of amber ones.