PPM Question, using tap water

I have read a lot of posts about Tap water PPM and I get conflicting information...
I use tap water in SoCal and after I let it sit overnight or even 48hours my PPM is around 600-650! (its about the same before I let it sit as well).
Is this bad? Do I really need R.O.?
Im currently 1 1/2 weeks into veg on a flood and drain system with rockwool and clay pellets, using a 25gal res. What should my PPM be at this stage? and do I account for the tap's 600ppm when adding nutes?

Also, Ive heard some people talk about adding Hydrogen Peroxide to their res, is this common or only if you have a bacteria problem?

Your opinion is appreciated!!

Always use the ppm of the water as your base number when calculating the total PPM. so its 650 plus nutrient levels..

Your grow would benefit from a RO


JP

650ppm is high before adding nutes. a RO will be beneficial for you. H2O2 i use it as a preventative to larvae, i use it 1/2 strength and it works great

Yes, I would say a reading in the 600's from plain tap is a bit high, but most water treatment varies from city to city and most of the chemicals put into the water are not readably digestible by the plant and/or evaporate. I get my water from one of the great lakes and my base reading is--after I let it sit about 15 minutes--a consistent 160 ppm. I then subtract that reading from any reading I take subsequent to that.

~ooli~

RO is a waste of money if you can drink it and not die its FINE!!!. Use the formula on your nute to add the proper amount to your size of res and focus on PH 5.8. The PPMs are a distraction just use the directions on the bottle and change out rez every 2 weeks. You probably will find keeping your PH at 5.8 to be a challenge in its self. Keep it simple brother and Good luck.

sparkafire said:

RO is a waste of money if you can drink it and not die its FINE!!!. Use the formula on your nute to add the proper amount to your size of res and focus on PH 5.8. The PPMs are a distraction just use the directions on the bottle and change out rez every 2 weeks. You probably will find keeping your PH at 5.8 to be a challenge in its self. Keep it simple brother and Good luck.

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it's not that simple, the ppm when too high will lock out nutes, 650 is already high without any ferts added to it. i don't use RO but my tap water doesnt exceed 250 ppm thats managable but 650 you can only add to it some 400-500 ppm of nutes thats not enough for plant to feed and if you go higher lockout occurs. in his case it's better to have a RO filter IMO

Damian138 said:

Is this bad? Do I really need R.O.?

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Nobody can give you an answer although many will. Here's the easy thing to do, try a grow and if your plants die your tap water is no good. If they flourish you're good to go.

Thank you everyone for your input!!
I think Im focusing too much on all the small stuff, like Japanfreak suggested, Im going to continue my current grow with tap and see how it goes. Ill just have to keep a close eye, make sure they don't get chem. burn... So far Im off to a bad start after a slight over watering problem... Damn rockwool!!

You will be fine Keep us posted.

600 ppm is the highest I have ever heard of,the problem is what is in it to bring it to 600,you could have a very high level of a certain mineral wich could cause a toxic build up in the plant because your also adding it in with your nutes,I would try on a small grow before you go pouring money down the drain,and as someone else stated if your starting out at 600 ppm that doesnt leave much left for nutes,I dont go over 1000 ppm on my plants anymore and they are doing just fine,I dont like pushing it untill I start to see nute burn on the leaf tips. I like my plants to be green not nute burnt tips. good luck