need feedback from experts on Metro treatment

[Miamiheat]

Hello,
I have a 450L tank with about 30 Discus from 2.5 to 6-7"
Tank is bare bottom and i have FX6, sponge filter plus a very efficient overhead sump.
Water change 30% daily or every 48h at least.
Very active fish behaving like happy guys. One pair laying eggs constantly in there.
I have seen 2 or 3 fish looking less lively or coming out with a white stringy poop. I am not sure how many could be affected.
So i have been diluting 500MG of Metro in a little bit of tank water and soaking my tetra prima pellets in there. I feed a few times in the morning and in the evening. Was thinking to do this for a week.
All fish are eating so I am thinking its the best way for me to put it in their system.
Any comments on that will be welcome: expected effectiveness? dosage?
Thank you for reading.

[Second Hand Pat]

Hi Stephane, you have 30 discus in about 118 gallons of water. That is way overstocked. In that size tank we would recommend about 12 adult discus. I would suggest the reason for the white stringy poop is stress due to overcrowding. Is there anyway you could reduce the stocking level? Also all the filtration in the world will not replace the need for water changes.
Pat

[Miamiheat]

Thanks Pat, I can't setup another tank at the moment but I will 2 or 3 months from now.
I believe if you have 30 kids or 30 pets of any kind you are always bound to have a couple with a cold or a little issue. I would isolate the fish if they were very withdrawn or not feeding but it's not the case.
Do you think the dosage, length of treatment (7 days) and method of delivery might yield me some result or not at all?

[Second Hand Pat]

Depends on the cause of the issue. If it is stress then treating with metro may not help. If you wish to continue this course I would suggest at least 10 days vs 7. Just ensure the affected fish are eating the treated food.
Pat

[Miamiheat]

Got you. Thanks very much.