problems arising in 3rd week of veg. state

[juice meat]

i have ten plants in the vegetative state growing under a 600 W HPS. four KC Brains X Mango, a plum crazy, a jack herer, a white widdow x blueberry, and three sage x mango. plants were started in rooter cubes, transplanted into 4 inch containers, and have now just recently been transplanted to 3 gal containers. my growing medium is a 70-30 peat moss - perlite mix. i added the recommended dose of hydrated lime per sq foot of medium to raise the ph to a more acceptable level. all veglings are between 5 - 6 1/2 inches tall and have shown vigorous growth up until this point. we filter our water with a berkey bucket system to take out heavy metals and dissolved solids, then adjust the ph to 6.2 before watering (handwatered).they have been on Canna nutes - (rhizotonic, tera vega, and cannazym) following all guidlines on feeding.
what sucks is this - no digital camera.

lower/oldest leaves are starting to show yellowish brown to rust colored spots and drying out before dying. i can't seem to decipher it as being a deficiency or salt build up in the soiless mix. all plants drain well when watered. should i go ahead and go through with the flushing? and if so, will this kind of soiless mix have any problem with being waterlogged? or should i just play it day to day trying to diagnose it as a deficiency? also, does anyone have any experience or advice for using Canna nutrients?

i know that some pics would make it easier for some of you to help me, hopefully i can find a way to get some up within the next day or so.

please any advice would really help me.

 

[Roken]

Welcome JM,
Glad to have you join the site and already taking part. I also grow in soil but i pesonaly use advanced nutrients so you might need another members opinion on the canna nutes, hear there great tho. I would say it sounds like salt build-up and would flush the soil, dont worry about it getting waterlogged because your going to let it dry out before watering again. What is the P.H of your soil? do you have a soil P.H tester? If you dont have one, try and test the runoff water from the bottom of your pot, after its leached the soil. This might give you a close indication of your soil's P.H until you can get a soil tester. Hope this can help, peace and love!!!!
Roken.