Hole in Head or just overly worried?

[Musky78]

Tank stats:
150 gallon
fluval fx6 (canister cleaned once per month)
waterchange : 2 times a week (55gal) 1/2 RO & 1/2 tap water with Prime conditioner
PH 8.2
Ammonia and nitrite 0ppm
nitrate 5ppm
temp: 85F
stock: 6 other sub adult discus
New fish added prior to symptoms: No

Fish seems fine otherwise, eats well, interacts well.112472112474

[jmf3460]

are you using carbon? are you adding back any minerals to your RO?

[Musky78]

Using Purigen (so yes). no nothing back into RO other than mixing it with 1/2 tap water

[Kyla]

Those look larger than regular sensory pits to me.

[jmf3460]

to me they look like mineral deficiencies. I have recently learned the hard way the ill effects of mineral deficiencies in my water. You might try removing the purigen, it could be pulling out all the trace elements from your water that could be causing these pits. The main thing a discus needs when these pits appear is often times calcium. This subject of carbon removing trace elements that cause pits over time, is a much debated subject, do some research on it.

I have a thread on it here http://forum.simplydiscus.com/showthread.php?129433-Long-Term-Carbon-Use&highlight=

[Musky78]

Thanks all. Removing my carbon and will see what happens