Ph Dropping PPM Is Stable

[Hydrofonix]

I'm using 5gal DWC and GH three part with RO water. she has stable ppm's but I changed the res 2 nights ago and set to 5.9 and it dropped to 4.9 cant figure out what's going on I checked the roots they are little stained from dye of nutes but cant smell root rot...... roots look ok only thing I see that could be a indicator for root rot is in the res there are many floating bits of roots is this root rot?............ im buying CANNAZYM will this help???

 

[Marzbadrock]

No hydro guy here but maybe try letting your reservoir bubble a for awhile then pH. Or add some pH up. Just throwing a idea out there for you, like I said I'm no hydro grower