A 5 gallon pot, by the 3:1 method would be getting flushed with 15 gallons.

That 5 gallon quasi-flush...likely just got things primed for another 10 gallons to be poured over them. But being as ya stopped at 5, theres likely a layer of unmentionables that the roots would like to be rid of.

Me, I flush using the 3:1 method...I do it with Clearex to fascilitate the breakdown and flushing of those unmentionables...then allow enough days to pass for the soil to dry down pretty good before the 2 times I give'm a drink with just water--no nutes...just water. Then back to feeding as normal till the next flush.