PH Dropping quickly?

[MisterE]

I'm sorry to post this question, I tried to search but the term "PH" is too short for the boards search function...

I'm having to PH Up my nutes more frequently as my plants grow. I'm wondering if this is considered normal, or if it is indicitive of any actual problems etc.

I only use 8 to 10 gallons or so total (going to change it out and measure carefully today) and the plants are only about 10 inches tall, on their 8th node.

I calibrated my continuous meter yesterday, and PH Up'd to 5.8, this morning it was 5.3 so I upped it back to 6.0 (couple drops too many, oops) and it's down to 5.9 already, only 2 hours later.

Any input on PH dropping appreciated, thanks.

MisterE Reviewed by MisterE on 12-14-2006. PH Dropping quickly? I'm sorry to post this question, I tried to search but the term "PH" is too short for the boards search function... I'm having to PH Up my nutes more frequently as my plants grow. I'm wondering if this is considered normal, or if it is indicitive of any actual problems etc. I only use 8 to 10 gallons or so total (going to change it out and measure carefully today) and the plants are only about 10 inches tall, on their 8th node. I calibrated my continuous meter yesterday, and PH Up'd to Rating: 5

[Weedhound]

Don't know Mr E, mine usually goes up as the plants get bigger. Only time i've had ph probs too low was when using new medium that I didn't rinse super well. You use RO water right?

[MisterE]

Yes I use RO water, some calmag as recommended (a little less than 5ml/gal actually), and weak gh 3 part nutrients. 5ml each per gallon currently.

I recently added a 400wMH and my water temp has gone up too high, does that create a PH issue?

My plan already for today is to drain the system, relocate my res to a new location which I've tested as several degrees cooler. But I dont know if thats related to ph. I also planned to go to latewoods feeding schedule which will be somewhat stronger nutrients.

[MisterE]

I'm also still dealing with the brown spotted leaf issue which I'd hoped had been corrected but it's still showing up. Red stems also. I know these could be related to nutrient lockout due to HIGH PH, but what about low? Yargh too many questions.

[Weedhound]

There is a range for ph...I believe it is 5.5 to about 6.2 but I'm sure others know better....anything outside the range will cause nute lockout......I'm sure 5.3 is dropping too low...no clues why it would be dropping like that.....sorry....

[Weedhound]

I would try the stronger nutes--latewood's formula too if you have run the other gamut--and it sure sounds like you have. I actually plan to try it myself next grow....i did have problems at one point not using ENOUGH nutes...can't remember if I told you about it......age...senility.....good luck

[MisterE]

Thanks, Weedhound. Yeah I have the chart for the various nutrients and their proper ph ranges etc. and have been keeping it at 5.8 as perfectly as I can. This rapid dropping thing is a new one.

It's at 5.7 now.

When I rearrange my room this evening, I'll raise up my grow tub a few inches so the system will hold overall a bit more water. Should make it more stable in general, and keep water temps cooler too.

Despite it all, the plants are doing well, crowding each other, showing pre-flowers and starting to give me a nice smell

[MisterE]

Well for anyone following along, I've rearranged my room to place my res in a cool corner compared to the hot spot it was at (my water temp would start around 68 degrees and climb to over 75 through the day, and I didnt like that). The temp at the ground level next to the res is 68 degrees. Looks like the right spot.

I raised my growtup up on 2 old phonebooks that were slated for recycling. Procrastination pays off! This allowed me to add about 2 more gallons total to my system, which should also help keep numbers more stable for longer, and temps lower. The exact volume is now 10 gallons. Perfect easy number!

I took a plastic straw and put it straight down into my res, and marked the waterline with a rubberband so now I can check water level very simply.

Based on my water volume and using the "latewood formula", I've come up with these numbers for Vegetative growth:

NUTES*: 10 gallon@8ml/gal = 80ml (1/4 cup + 1.44 tblsp)
*this is for EACH of GH 3 part. Flora, Micro and Bloom.

CALMAG+: 10 gallon@3ml/gal = 30ml (2.08 tblsp)

I've released my attic hatch which allows the warm air to vent naturally, and the ambient room temperature at the canopy top is now at 77 degrees. 400watt lamp is about 14 inches above canopy, and I have cool white flourescent shoplight as side lighting.

As to the PH, it's currently at 6.0 with the plain RO water. I'll nute and supplement it in the morning with the exact numbers above and monitor through the day. PPM is currently at 20.

If any of this sounds wrong or anything, let me know.

Thanks for watching! hehe imp:

[Weedhound]

I'll be interested to see what it is in the am before you add nutes etc...

[MisterE]

Hi Weedhound, this morning the ph was still at exactly 6.0, and ppm still at 20.

I've added the 3 part nutrients to my res a few minutes ago, and after an hour or so it should be fully circulated in my system.

After adding nutes, the PH dropped to 4.8. I know I'll need to PH Up it after it's fully circulated. We'll see just how much later on.