LED Grow Light Forum

Hey Happy,

SME has covered a lot of what you were asking about but one suggestion I would make would be to use RO water with the LF and not tap water. I don't have a RO system: I don't like how much waste water they create. We need all the water we can get out here in Colorado. I have 4 5 gal jugs that I fill up at Wallyworld. 37 cents per gallon. My tub uses 10 per rez change and then I have left overs for the addback part of the LF.

What I use for tub additives is Aquashield during Veg only. When I switch to 12/12, I use an enzyme. Hygrozyme, cannazyme, etc etc. and then halfway thru flower, I use the enzyme again. The enzymes eat the old roots which produces food for the plant and also stimulates new root growth. After halfway, my theory is that I don't want the plant to use energy on the roots. I want it for the flowers!!!

I'm with SME too. Flushing not needed with LF. Unless your PPM's are high, Lucas said so himself. There are 2 "posters" on many of these grow sites that I have learned the most from: Lucas and Heath Robinson.

Man.....it was tough waiting for the lights to come on this morning so I could go check on my girls....

I was in there as soon as that timer clicked....searching for any signs of distress! The only thing I could find was one plant has slight nute burn on it's tips, but not all tips. Everything else looks at least as good as it did yesterday.

PPM dropped from 1200 to 1190 during the night so I guess the plants are drinking a little. Ph is still steady at 5.8. All my girls are looking great!! At least to me....if you see any reason for concern in the pics below please let me know...

Two weeks of 12/12 and got pre-flowers at just about every node, but no flowers yet..

As usual, comments, suggestions, advice & general bs is welcome....

Happy

Rkymtnman,

Thank you again for the info!! Much appreciated... What are the advantages of RO water??

Two reasons that I opted to try my tap water first:
1. When I change water, I drain about 70 gallons of old and then mix up 70 gallons with new nutes. The Aeroflo alone will hold about 40-60 gallons, depending on water level in the grow chambers. That is a lot of water to have to haul!!! Thankfully I had the foresight to install a utility sink in my room.
2. My tap water is pretty good. Actually the area I live in was recognized a couple of years ago as having one of the best public water systems in the nation. Straight from the tap my water tests 34-35 PPM and 7.0 Ph.

Yesterday was water change day and my back is still hurting!!!

After mixing in the LF nutes (8/16) with my tap water, Ph is right at 5.6.....so with just a couple of drops of Ph up, it puts me at 5.8.

If I see anything going wrong, RO water is top of the list....but so far using tap seems to be doing ok.

Keep an eye on me Rkymtnman....and keep me in check.....I do need the help!

Thanx!

Happy

RO or distilled water is the key to the LF. Not sure how much you researched on how the formula was derived but basically it 's based on Mel Franks's nute profile for MJ. it's like 100-100-200 for flower. Lucas found that GeneralHydro nutes with just micro and bloom had the identical profile.

The RO water comes into play because tap has trace minerals that would offset that 100-100-200 ratio. Your ppm's are low which is good. But how does it breakdown? is it from cal, mag, etc etc etc. Some tap PPMs are 400.

The key to LF is your PPM meter. I use EC for simplicity. there is no .5 or .7 conversion factor. Let's say your PPM is 1000. After 24 hrs, it drops to 700. WOW! they were hungry. so now you know that you need to be way higher than 1000.

After 24 hrs, it goes up to 1100. They aren't hungry. They are using more water than nutes. So 1000 is too high.

After 24 hrs, it is at 1000. Perfect!!! they are using the perfect mix of nutes and water.

Don't get hung up on the 8/16. Just keep in mind it's really just the 1:2 ratio. Finding what PPMs the plants need is the key

Cool!! Thanx for the info...it does help make sense of this...I think...

So by my PPM only dropping 10 points over night means that my mix is pretty close to their current needs?? If I was way off on their needs the swing in PPM would be greater...plus or minus?

exactamundo! you are really close at whatever PPM your plants want to be at.

have you looked at doing the addback part of the LF?? there are many growers who go all grow WITHOUT a reservoir change. since your res is so big, might want to do some looking into that part of LF. plus no additives. saves alot of cash too.

Actually, the 100-100-200 part of Franks formula is talking about NPK so 35ppm of trace minerals shouldn't impact that ratio at all. The reason LF is based on RO is because everybody has different water and if everyone starts with RO then the mix will always be the same. Since HW has such low ppm tap water it's worth trying, but it wouldn't hurt to get a water quality report from his source, they might even have it online. I imagine that his tap water is RO water that was further treated with fluoride or chlorine and perhaps some trace elements like calcium.

Actually it is 8/16 per gallon but some genetics can't handle the same amount of food as others so Lucas says to dilute it down a little by adding more water if the plants cant take it. There are factors that help plants be able to use more food.

I do remember reading something about the add back part of LF....but will need to read up on it more before trying it...

Thanx!

that's what I was thiking SME. his PPM is almost RO like. happy won't have any issues with LF. but a water analysis would be neat to have if deficiencies arise later. could be easy to diagnose.

and some more info for anybody else following: Lucas recommends 5/10 for low light conditions (CFL) or 8/16 for HID

who knows, maybe this LED would be better at 6/12 or 7/14. the 1 to 2 is all you need to remember.

That is a good point, perhaps LED plants do need less food and that might also explain why LED doesn't yield as much as HID typically does. Personally, I'd attribute that to less penetration/intensity and therefore less light all over the plant so they can't use as much food. That might be something to experiment with for LED.