Flushing and RO water

The reason you can't take an accurate ph reading with RO water is because there isn't anything in the water.

This is a quote from this site.

An electronic pH meter is just a high impedance Volt meter. If the
resistance of the medium is too high, and one is using a *glass*
electrode, (not quinhydrone/sat. calomel half-cells) -- the reading will
drift -- because the instrument can not reliably measure the 59
mV/decade that it is required to do, to measure pH. This is easily
provable, if one has access to *fresh* (without dissolved CO2) 10 megohm
(or better) water then the drift is very obvious. (The quinhydrone/sat.
calomel half-cells are not something that a hobbyist would want to try
either.)
Click to expand...

I just tried it with my new ph probe which is a Hanna and it stablized at 6.7 but as soon as I moved it is started dropping right away down to like 5 something. My old meter would read the same water as 8 something.

BTW, pure water does have a ph of 7 I believe but as soon as it hits the atmosphere it starts to absorb CO2 and CO2 lowers the ph. Since there is nothing in the water to buffer it the CO2 alone can cause quite a drop.

Thanks Racefan for answering my question.
 
Very true, it does drop fast, usually down to 5.5ph. RO water has no electrlites. Problem solved, use a cleaner like floraclean during final flush. It has buffers or just use the water. Once it goes thru the medium you should be around 6.3. These numbers are what I experienced most when work with aquariums with a good reef eco system and with my own gardens. Just remember that the final ph will always be below 7.0 before a ph upper is used but you want the lower ph for better water absorbtion.
Don't know if any of that might help but its what I experienced so far and I have never seen this printed in a grow bible as of yet.
 
There's nothing in RO water to measure. It's the best "water" for feeding/watering.

But I like the Floraclean finish idea too.

Another thought...if it's only a week til chop, does it really matter if the PH is wack? Answer - YES. It puts on the extra weight and THC production during the final stages of flower.
 
Akorn said:
YES. It puts on the extra weight and THC production during the final stages of flower.
Click to expand...
Which is why I don't advocate 2 week or longer flushes. IMO the plant is trying to put on as much weight as it can in the last days and your starving it. That seems counter productive and extremely stressful IMO. I myself think 7 or 8 days is plenty of time for flushing. Just my opinion here so don't tear me up too much.

As you guys can tell, even though I tell new growers they are a must, I don't use a PH or TDS meter. Or even RO water for that matter.lol I don't even measure my nutrients. I have a old oxyplus pump bottle and I give the plants between 8 and 12 pumps per gallon.lol As long as they are green and not burning, I'm happy. :cheesygrinsmiley:
 
You have become too comfortable with your grows my friend^
With out proper measurings and recordings it makes it more difficult to know if your excelling to reach the full potencial of your grow. Also makes it harder to solve a problem and when the problem accured. I have done what you are doing but I prefer to record my grows to compare. I want to know the maximum amount of plants I can grow and the maximum height to flower plus I want to know the minamum too. Maybe I just go too overboard with my hobby.
 
Yeah...I've probably gotten way too complacent. I grow way more than the girlfriend and I can possibly consume so I guess I'm happy. No need to improve only to waste the gain IMO. I give so much away to those I know already that any more and they will know I'm growing. Some already ask how I can afford to gift a oz or more every time we visit.lol I just smile.:cheesygrinsmiley:
But your right. I should be practicing what I preach. I have the meters. I just don't use them. Well considering the nutrients I use, I can only use one of them.
 
Yea, we have a good grow support here. Is your RO a RODI? Reverse osmosis with a deionizer? The membranes can get pricey but The water is really pure and once the nutes are put in the ph does not seem to waver as much. Good luck and grow well.
 
All this talk of RO water, I have a RO drinking system in my sink. So i have been feeding my plants using it, but the ph is a good 5.5 to 6.0. Is RO water naturally more acidic or is my filter bad? I tested it using some ph chemical (phenyl?) from general hydroponics.
Gorillabudz, whats your opinion on distilled water for plants?
Thanks
 
Racefan said:
Which is why I don't advocate 2 week or longer flushes. IMO the plant is trying to put on as much weight as it can in the last days and your starving it. That seems counter productive and extremely stressful IMO. I myself think 7 or 8 days is plenty of time for flushing. Just my opinion here so don't tear me up too much.

As you guys can tell, even though I tell new growers they are a must, I don't use a PH or TDS meter. Or even RO water for that matter.lol I don't even measure my nutrients. I have a old oxyplus pump bottle and I give the plants between 8 and 12 pumps per gallon.lol As long as they are green and not burning, I'm happy. :cheesygrinsmiley:
Click to expand...
Your either a god or very lucky....no ph no ec
Sheeeezus
 

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