First time poster, Long time lingerer

These problems have been occurring for a long time and I have never found a solution so the plants have suffered for some years.

Right now there are some plants growing in a homemade tube system almost exactly like pictured below. The ingredients consist of PVC fence posts, PVC pipes for the manifold, plastic reservoir, PVC glue to hold the manifold together, Plumbing grade rubber tubing to connect the Rubbermaid top-off reservoir, a pump, and Aquarium Goop. The reservoir holds about 15 gallons and with the tubes included there is about 20 gallons in all. The top-off res hold 50 gallons.

Now here is the problem and hopefully some knowledgeable person can help because I have exhausted my brain in trying to figure out what the problem is and Google offered me no answers!

Many different strains(Indica & Sativa) and different types of Nutrients(BC Hydro, Dutch Master, and General Hydroponics) have been tried all with the same result/problem. The plants grow fine in the clone/vegetative state. In fact, they grow great! The problem occurs only in the flowering stage. Two weeks after inducing flowering the PH will start to drop. When the nutrients are first added to the reservoir after a nutrient change the PH is at a healthy 5.6-5.8. Within 24 hours the PH drops to an aggravatingly low 4.4 while the PPM stays the same! This means that 40ml of PH-Up has to be added regularly on a 24 hour basis to get it up to around PH 6.0!

Now, I have read that PH levels may drop because the plants will eat more water and therefore leave more nutrient solution in the system causing PPM to rise. I would agree that this is the problem if only the PPM did rise but it doesn't.

Needless to say, all this PH fluctuation wreaks havoc on the nutrient availability of the plants. There has never been a healthy crop and it is sad really because from what I can tell everything has been done by the book.

The water used in the system has a natural PH of 7.0-7.1 and a PPM of less than 100. The plants sit in small four inch pots with aquarium grade stones.

The nutrients used are General Hydroponics Flora Series at a ratio of 1-2-3 during bloom as indicated on the label. PPM has been tried anywhere from 700-1300 during this stage with the same result. A ratio of 1-1-1 has been tried and the Lucas Formula has been tried as well.

What am I missing? Why is this happening? Is there anyway to fix this problem? Any help would be greatly appreciated and if more info is required from the reader please let me know and I can provide it

Attached Images

Aeroflo2.jpg (23.7 KB, 3 views)

IMHO, with that many plant sites and that small of a res. its gonna happen.

also used GH 3-2-1, 1-2-3 for quite a few grows initially in a 3" tube system with small res. 18 gal/28 sites.

went to buckets with 6" netpots and 20gal/6 plants still had the problem you have,just not as bad

SO, checkout Latewoods legacy a sticky post. it uses a whole different GH reciepe, and it works much better
the Ph runs more like it should. stable until nearing a nuit. change,then it starts changing about 0.1-0.2 units daily

Do you make up with Ph water or a nuit solution?

Read Latewoods legacy

...Latewood's Legacy: GH 3-part and CalMag tutorial and discussion

__________________
"Consider yo' bad self enlightened, homeslice"-StinkyAttic

Thanks for quick replies guys

So your PH drops into 4.5 range within 1-2 days also? Changing to a bigger res helped? If so, how much? What is your PH drop like now? What size res should is good for 12 plants that end flower at around 2' tall??

The system is topped off with regular tap water @ 7.0 PH and less than 100 PPM.


Does the recipe work without a reverse osmosis filter? Economical situation is bad and they look to be around $300-$500

EDIT: It seems strange to me that I could not find any threads anywhere on this problem. I must of googled every possible variation on this problem, searched endless amounts of threads, and found nothing concerning this problem. Could it really be something as simple as the res is too small?

Hows it going Dutch?

actually I went to a 40 gal Panda for the pipe system, then to 12- 5 gal grow buckets on the 40 gal, then switched to two 20 gal GH tanks each one feeding 6 buckets

In the beginning I tried to stay around 5.2 Ph, but it meant constant adjusting

changing to Latewoods method plus bigger tanks pretty much solved the big dive,now its a slow drift UP

I have been looking at an IntelliDose ph controller by americanhydro

what color are your roots?

100 ppm water should work just fine ,no need for a RO headache, maybe a carbon filter but you will need to measure ppm before and after filtering to see if it changes

Roots look pretty healthy. A little staining from the nutrient solution though.

(The plants sit in small four inch pots with aquarium grade stones.)

This is the only thing I would question. You sound like your doing your homework well. And trying many times with same results. Those stones sit too close toghether and do not hold water for a cation exchange. The roots by flower time may be like root bound and choking off by then. That's why they do good in veg, plenty of room.

I would go with another medium. Hydrotron or rockwool or lava rocks just to see. You have studied and tried almost everything else.

Do a search here for Loc Nar. I started with drip system with 6 plants to a 5 gallon tub. Only when I change nutes did I have to down my PH for a day or so.

Pic's of plants and roots would help greatly. You have come too far to give up now. If you over come this it's bud city. And what's the lights and heat in your room and rez ?

Thanks you guys for all the replies. Sorry for the late response.

The reservoir has been upped to 40 gal. Hopefully all goes well and the PH doesn't plummet like before!


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The nutrient regiment is going to be switched over to :

1=ml

Week 1-4

45-175-350/PH 5.5(is ph 5.5 good for this stage?)

Week 5-8

0-175-350/PH 5.4-5.8 going up .1 every week

Reservoir will be topped off with 4ml of CalMag+/ top off water will be 5.8 PH
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The nutrient mixture is for a 35 gallon res but from past experience with nutrients, less is more. Do you guys think that this will cause nutrient deficiency? Nutrient burn is scary

Thanks again

Roots look to have enough room. The tubes are 80% full of water and they sit in the solution and no light seems to be getting in. Roots look healthy as well. Sorry for double post but I can not edit the above post for some reason.

Bumpity Bump-


Any word on what you guys think about the nutrient regiment I proposed?

EDIT: Where is the rep button? I cant seem to find it on these forums

I will only comment on what I have experience with.
that being said HAVE you read latewoods legacy??
do you understand what he says?

Still getting the Nutrient dive with the 40 gallon res.........


Yes I understand legacy's nutrient formula and ended up bumping the nuts up to around what he recommends. Waiting on CalMag in the mail. Would the lack of the MAg/Cal cause nutrient drop?