Tap or RO water to flush salt build up?

So i feed my girls in promix hp with synthetic nutes. My schedule is feed, feed, feed, feed then heavy water with Tap water to remove any unwanted salt build up. Each of these waterings are 48 hours apart.

My question is should i be using my pure RO water for the heavy watering or my well water that is 6.5 ph and 300 ppm.

After that heavy watering, would you wait the 48 hours to let the promix hp dry back before the next feed or give them a little feed immediately after flush so they can have a little food while they wait on the next feed cycle?

I grow in promix with synthetic nutes and I always feed, never flush and permit no drybacks. If you're worried about salt buildup just keep feeding, maybe lower your dose.

shnkrmn said:

I grow in promix with synthetic nutes and I always feed, never flush and permit no drybacks. If you're worried about salt buildup just keep feeding, maybe lower your dose.

Click to expand...

On their site they say Promix hp needs slight drybacks. It says water when the top turns light brown.

Nevertheless, I flood my pots to runoff twice a day. My point is the nutes running through frequently prevents any salt buildup. Drybacks means dissolved nutrient solids not taken up by your plants fall out of solution in your medium. Also, Promix becomes a little hydrophobic when it gets too dry and then it's difficult to rewet and you get uneven moisture distribution.