Lower leaves dropping periodically.

E-indoor or outdoor---Indoor
E-soil, soilless, coco, aero, or hydroponic---Hydroponic
E-specific medium---Rock Wool
CSL-Soil type/brand---N/A
HCL-Hydro/aero/soilless system type---Bubble Hydrophonic 6 gallon tub.
SCL-Anything you have added to the soil---N/A
SCLR-Soil or slab runoff pH---5.75
E-Water source---Bottled RO
E-Source water pH---5.75
HRT-Source water EC (if hydro)---9
E-Age of plant---20 days
E-Type of fertilizer---Came with setup. No name. Followed directions on packets.
E-Rate of application (if hydro, this is your PPM number, preferably after each component is added)---9EF
E-Lighting source and distance from plant---CFL 3"
E-Air temperature (both day and night if you are running a dark period)---lights on N/A
HD-Reservoir temperature---unsure
E-Air % Relative humidity---30%
E-Lighting schedule---24/7
E-Type of ventilation your room has---4 fans
TR-Did you pre-soak your media in pH corrected solution?---no

I have been growing these plants with 2 bubble rings and
change the water every 2 weeks.
After the last change, I managed to damage one of the plants root system. The other is growing very fast.
My question is , is it normal for the bottom leaves to fall
off when new growth is sprouting from the node. Can I
cut off the parent leaf after the new growth has started
and the old leaft is dieing?

As an aside, I would love to know how to post pictures.
Thank You.

I just tried to upload and post URL from my Picasa Viewer and was cut off of the forum. I just can not get pictures posted. I apologize.

don't remove leaves ... unless drastic leaf-loss is happening, things are 'probably' OK ... bottom leaves yellowing, and dropping off, is perfectly normal ... it's just part of the aging process, as the plant draws from it's fan leaves ... (side-note: your RO water doesn't contain necessary micro-nutrients, like calcium, iron, magnesium, etc., etc. ... look for other sources, or start adding Cal-Mag+, Earth Juice Micro-Grow, etc..) ... good luck :smokin:

Thank you. I add nutrients every time that I change the water and test PH regularly and add PH Up or Down. I also
have a nutrient tester that is temperature sensitive. I am relieved that the leaf dropping is normal. Thank again for the
peace of mind.
Cheryl :)