having serious PH spikes in rockwoll, please help

[somedude56]

Any help is greatly appreciated.

Like the title says I am having some serious ass ph spikes, I just recently transplanted into 4x4x4 from starter cubes, running h and g's entire line of nutes with great white, about 2 days ago I noticed things starting to get yellowing/droopy and in the last 24 hours things started happening real fast, so I checked the runoff and it was coming in at almost 7.0 ph :sweating and had to of been locked out. So I flushed THOROUGHLY, checked my runoff (5.6-5.8) and then hit em with a 550 sol. of mild nutes 5.6 ph (my tap comes out at 220 so that comes to 330 nutes, pretty light), leave for a few hours/come back and now im getting runoffs of 6.0 ph already. WTF is going on? Does anyone have any experience on this? The cubes were soaked for quite a few hours before anything was transplanted in a 5.6 nute sol.

Here is the complete nute. list I've been using for mixing sol. give or take a little. 3ml per gallon of A and B aqua flakes, 1.2ml gallon Roots excel, .1ml per gallon drip Drip clean, 1ml per gallon algen, and a little great white. The roots are going great, i got roots coming out of the 4x4 already but wtf is going on with the crazy spikes all of a sudden? Thank you very much for any help, I really appreciate it.

 

[impulse_ak]

check rez temps

 

[hiboy]

I've ran rw for two years now. If i do a rezzie change which is every week, the next day or so the ph will jump for sure. I usually start it at 5.7 and let it swing to 6.5 tops, less than that if i catch it in time.
Usually it wont jump much after a couple days. You might want to calibrate your meter or check it to see if its all good. Whats ur ppm in your rez.
h

 

[iscrog4food]

Is this a recirculating system? Also do you have a good sized air pump in your rez? When I used rockwool I would presoak and do a complete rez change after the first 3 days if in a recirculating system. I also find that adding silica helps keep the ph more stable once you adjust it. Also +1 for calibrate your meter. Rockwool has a really low CEC so the Deficiencies could be from you feeding too little nutes but check your meter first.

 

[Gaval]

if your using tap water you will get crazy spikes in your ph. I would invest in an r/o system

 

[sky high]

pH swings in rockwool....especially at the onset of transplant means that you didn't FLUSH the cubes well enough..or at all..which is the mistake most peeps make.

The Grodan folks told me directly that you should run tap water through the cubes for a few minutes each to rinse them of the LIMESTONE dust that is present in the manufacturing process. This dust needs to be rinsed away BEFORE the 5.5 presoaking or it just goes into suspension and ends up back in the cube causing..yes...your pH to rise.

hope that helps in some fashion...if not now, down the road.

s h

 

[Texas Kid]

What Sky said exactly......

Tex

 

[freegrow]

?

I dont think 7.0 would do this this fast ..........Im not gonna say it but look for bugs ......and what is your root color ? JMO I could be wrong but ph doesnt yellow that fast and are the leaves twisting and curling ? this is a sign of ph prob

that ph will stop growth but yellow and droup in 24 hours ?

 

[somedude56]

thanks for all the posts guys, everything didn't happen in 24 hours, things just really started to go downhill fast the last day before I caught it, just checked it again last night and it was in the high 6's, I have been religiously checking my solution PH after I put nutes in. At this point I am stumped so I'm going to put all the info out there. Right now I'm running a 720ppm sol (my water comes out at 220 already so 500ppm nutes), I'm using a bluelab ph/ec/nute. temp meter and I have both bottles of 7 and 4 cali. sol. and yes it is calibrated fully. When I soaked the cubes they sat for hours in a 5.5 solution and since then they have been flushed 3 times with multiple gallons of just ph'd water and then fed with a 5.5 nute sol. that was around 670ppm(it comes out 220ppm already so 450) and it has spiked back up twice now.

as of right now I am not flooding the table, only 7 4x4 cubes are there and I just pull them out and pour the sol. over them until it drains out the bottom, I have let nute. solutions sit for a few days to and the ph has never changed. I am using tap water but I really don't know how that would cause this, especially since someone has already used this house and exact room as I am before to do a job, the only difference is he used hydroton rocks, not rockwool and he never did anything to the water as far as I know. I am seriously frustrated at this point, thanks for all the help guys.

 

[somedude56]

update.. right now I'm running some 5.2 sol. through them to try and get them down and now I'm getting runoff of 5.8-6.2 so they'll be alright for a minute.

More info- the solution that I'm pouring on them is 74.5 degrees and the growing medium is roughly 73-75 degrees and the ambient air shifts anywhere from 78-85 degrees throughout the day depending on the time of day.

EDIT... I just did a little experiment where I cut a piece of rockwool off of one of the cubes and stuck it in a little cup with some 5.3 sol. and the PH has already increased to 5.5...............

 

[somedude56]

I'm not sure if this could have caused the problem or not but I sure as hell fixed it if it was, I have a misting humidifier right in behind my little fan and the entire time the fan has been pulling the mist and the air has been going right across the them, this makes sense to me how it would keep rising up everyfew days as the high ph regular tap water im running through the humidifier would build up in them. Could be wrong but I'm clean out of ideas at this point. Humiditys been staying at 60-70% with the humid. behind the fan

 

[baba G]

Not sure if you stated already but what is your pH out of your faucet?

 

[somedude56]

water comes out the tap at 7.5 give or take a point or 2, earlier I had my air pump running with 2 stones in a 5 gallon bucket with a few gallons of sol. I haven't been keeping stones in the buckets yet and this was the first time, I ph'd the solution after adding everything and later I came back down 5-6 hours later and the ph had gone up to 6.6, it had to of had something to do with the stones and air pump running because I have let buckets of sol. sit overnight and checked the ph in the morning with no problems, anyone have any input on this? I'm going to look into getting my water analyzed as soon as I can.

 

[mastacheeser]

im not sure if you want to recirculate that great white
benes + recirc= ph headace.

 

[baba G]

Hey somedude56:

No matter how much pH down you add to your solution your pH will work its way back to 7.5 that it came out of your tap at!
I'd work on finding a nutrient blend that lowers it itself versus adding pH down as the pH down doesn't seem to have as lasting of an effect as the nutrients will at holding your pH down where you want it.

I wouldn't recirc benes either as mastacheeser stated.

What are your ppms or E.C. outta the tap?

 

[baba G]

You can go R.O. with your water....

Or since you have this problem, defeat it easily, drain to waste.
Just an idea

baba G