Help! Grow out tank gone crazy!

[Klawz]

140litre, bare bottom grow out tank.
16 baby discus between 3cm to 5cm total length including tail.
30 degrees, Ph 6.6, Gh 3, Kh 3, Nitrites 0, Amonnia 0
20 litre water changes daily with 40litres twice a week
Internal sponge filter and ehiem 2213 (no carbon)

After doing a 40litre water change today half the fish are acting sulky and seem extra skittish with three going completely bananas!!!
When spooked they zoom around in circles, up and down and around losing thier minds!! Getting stuck on spray bars, banging into things to then sorta float for a minute before regaining conciousness and then trying to hide.

Did water changes in three other tanks at the same time, two of which ( another discus tank and an apisto tank) getting the same treatment as in the use of prime, amazon conditioning salts and Aqua Pics Discus Kh stabiliser. The other tank being a guppy tank. None of the other fish in any of the tanks seem to be acting any different at all.

Only thing different lately is ive fed some live black worms yesterday but once again that was to all fish.

Since done another water change of 40litres.

Any help or ideas appreciated. Please even sms me on 0488220143 if anyone has ideas otherwise ill check here reguarly.

Just to add, there are six very small bristlenoses acting normal and some cherry shrimp with no noticable changes in behaviour.

Thanks in adavance Daniel

[ILLUSN]

theres something wrong with your tap water, the zooming in circles and slugish-ness sounds like chlorine poisoining

how do you age your water? are you 100% sure temp, PH were IDENTICAL before you did your water change? (ie the water you added to the fry tank had a temp of 30C and a pH of 6.6)

how much prime are you using?

does the tapwater smell even slightly "bleechy"

[Klawz]

theres something wrong with your tap water, the zooming in circles and slugish-ness sounds like chlorine poisoining

how do you age your water? are you 100% sure temp, PH were IDENTICAL before you did your water change? (ie the water you added to the fry tank had a temp of 30C and a pH of 6.6)

how much prime are you using?

does the tapwater smell even slightly "bleechy"

Temp and ph of the water i used for the change werent exactly what the tank runs at but ive changed water countless times like this. Taking tempered (not necessarily 30c and usually spot on ph7) water from the tap adding salts, prime and kh stable recently and adding it to the tank.
I dose prime at about 1.5 times recomendation.

The fish are still quite sulky and freaky but havent lost a fish as yet.

Where to go from here?

[ILLUSN]

Stop feeding for 24 hours and leave the light off.

Give the fish time to recover, if I'm right try adding prime TO YOUR AGING BARREL @ 2x the recomended dose (I use SAFE @ 3x normal dose but my tap water is PATHETIC)

after 24 hopurs try feeding again and if they eat your all good, maybe step back the water changes to 10% daily.

[Klawz]

Lights are off.
Now im playing the waiting game.
Thanks Illusn!!!!!!!!!