Afraid of over-fertilization.

First post on the forum, whats up guys? Looking forward to the community of likeminded individuals! Im currently two months into my first grow and i have two lovely females (one hashberry, one blueberry from bag seed) just starting to bud. They've been under a 1000 watt HPS over them, about 6 or seven inches above the tops. I've been watering only once the top two to three inches of soil is dry and fertilizing with a half strength solution about every fourth watering, so every other week. However, the leaf tips about halfway up on the hashberry seem to have burnt and some of the leaves are curling upwards on both plants. I know the fringing of the leaves is signaling of toxic salt build-up. Should i leach and give quarter strength solution or should I just stop fertllizing untill the plant needs it?

First off.. is the ventilation good in your room? A 1000w HPS 6 inches off the top of the plants is going to produce a hell of a lot of heat if not very well vented..

Now on to your question.. A sometimes quick and simple fix is to flush the plant, have you tried that yet? Just put it in a big drip tray one day and give it a gallon or so of water and let it drain and then put it back into your garden. Sometimes the nutrients can build up on the roots, keeping them from being absorbed by the plant. Try that and if you have no luck we'll have to look further..

the temperature in the room is a big problem.
i am running a 1000watt HPS in a silver star air-coolable hood but i am using an inline duct booter to vent. I want/need to step up the ventilation to either a squriell cage blower or a cheaper inline fan. My budget is extremly limited so I'm trying to find the economical option. I am looking at spending anywhere from 70 to 120 on a new fan, it needs to be able to be mounted on the wall and able to attach a carbon filter to. Any suggestions?

secondly, I flushed the plants with three times the volume of soil (they are in three gallon pots so I flushed with 9 gallons in each container, the last gallon with a dilluted nutrient solution). The leaves are ceasing to curl upwards but the heat has cause the leaves tp stretch upwards to dissipate moisture.

you can get a 140 CFM Dayton for around 80 bucks and the 465 CFM for about 95.
you can attach just about any fan to just about any carbon filter with duct work/fittings. Though you should try to get the correctly rated fan and carbon filter for your size grow area. (The CFM for the fan should be about three times the cubic feet of your grow area).

Best bet is to have a different fan for exhaust and cooling your light.

Like stated above you need to keep your temps between 75 - 85 TOPS!!!. AND PUT THAT LIGHT UP to just a little over a foot away from the plant. You might just be frying it! I never keep my lights that close. Hey If you keep this plant in an 85 and higher enviroment for more then a few days, good chance you'll get mites, A real pain in the ass, esspecially when blooming. Anything at what you're describing is murder.

I'd even keep that 1000w 18-20 inches off the tops of the plants. That's a lot of light very close to only two girls.