Any success with no to low reservoir change, just keep topping w/ R/O and nutes

The 0 change for the whole cycle method REQUIRES pathogen control. Namely H2O2.

To the copy/paste reply about H2O2 earlier; It works 100% of the time. No questions asked. Kinda like the lucas formula. I've seen the post you copied before and dismissed it given my personal experience and the teachings of the guy who got my on H2O2 to begin with. The great Al B Fuct

Bob Smith said:

Just to keep everyone in the know, I installed my R/O filter....................my pH and TDS beforehand were 7.5/150, and afterwards, it's at 8.0/3.

Not sure how the fugging pH went up (as the main reason I purchased the filter was to throw away my pH down - that's clearly not happening, but such is life).

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The meter reads 8.0 but that is not the pH of RO.

RO has no ions and your meter cannot read it.

If you add anything to RO
so you can read it
then it is n ot RO anymore.

I highly recommend that you avoid putting your pH probe into RO water
as it will eventually do permanent damage to your probe.

You should only measure the EC of your RO,
but never try to measure the pH.

The pH of RO is 7
but since there are no free ions
the meter cannot measure it
and you get 6.5 or 8.0

That is why you need to use 7.0 calibration fluid to check your probe,
since 7.0 cal fluid has the free ions necessary to read that pH

Earl said:

The meter reads 8.0 but that is not the pH of RO.

RO has no ions and your meter cannot read it.

If you add anything to RO
so you can read it
then it is n ot RO anymore.

I highly recommend that you avoid putting your pH probe into RO water
as it will eventually do permanent damage to your probe.

You should only measure the EC of your RO,
but never try to measure the pH.

The pH of RO is 7
but since there are no free ions
the meter cannot measure it
and you get 6.5 or 8.0

That is why you need to use 7.0 calibration fluid to check your probe,
since 7.0 cal fluid has the free ions necessary to read that pH

Click to expand...

Hmmmm, thanks for that - anyhow, took the pH after I added nutes (8ml/gallon of FloraNova Bloom) and it was at 5.6 pH, 1.9 EC.

Yeah...whatever the hell all of that means. RO water doesn't mean you can throw out PH Down by any means. It's almost unrelated, although the ph does change through the filtering process it won't change your need to adjust the ph and to keep it in range throughout your grow and when you add nutrients.

laserbrn said:

Yeah...whatever the hell all of that means. RO water doesn't mean you can throw out PH Down by any means. It's almost unrelated, although the ph does change through the filtering process it won't change your need to adjust the ph and to keep it in range throughout your grow and when you add nutrients.

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Well I'm certainly not throwing away my pH down yet, but from everything I've read about the Lucas Formula with RO water, the nutes are basically your pH down, if that makes any sense.

Hoping I can get by without using it, but I'll have it there just in case.

As usual Earl is back ass backwards. RO water has a pH, although the pH you usually get on a fresh RO watersample is inaccurate because RO filters do not remoce CO2. If you had any calcium carbonate in your water and most people do, the RO filter removes the calcium but leaves behind the CO2. This skews your pH reading by saying your pH is acidic as CO2 will form carbonic acids. A ph meter reads the ratio of OH- to H+ ions, they are present in RO water. If you let your RO water sit over night with some aeration the excess CO2 is dissipated and you should get a pH at or very near 7.o. The lack of ions (salt) means that water can not conduct electricity. A conductivity reading is based upon the ability to read the conduction of electricity through water via the ions. There are cells (probes) for conductivity meters that are made for specific ranges. For example to read very purewater you want a cel with a cell constant of k=0.05 to 0.1. However most cells are k=1.0. (consider mid range default range) though they may get a reading the reading will not be accurate, they might even read zero with a TDS level of 20. Who knows.

It is simply that a cell will get accurate readings within a range, so if it reads accuratelly nera zero it will not read accuratelly nera 1000 and vice versa. Do not expect a lot of accuracy from a $30 pin TDS meter. Good conductivity meters are quite expensive with the probes alone costing several hundred dollars.

I fully expect Earl to now say how wonderful his cheap meters perform and how pleased he is with them. Go ahead Earl.

The only reason you should not put a pH probe in RO water is for storage of the pH probe. As there are few salt ions in the RO water the silver and the chloride ions from your pH probe will be drawn to the nearly Salt ion free RO Water therefore greatly reducing the life span of the probe. Other than thatlong term soaking of the probe in RO water it has no adverse effect on a pH probe at all. It is safer to store the Probe in tap water than RO water.

Nutrients do not serve as a pH down. Typically they are pH balanced to around 6, so while thery would take the pH down a very slight bit they would not begin to take them down to desired levels of 5.8 to 6.3 if you have a pH above 7.

I noticed what was said about H2O2 earlier, I cant use H202 cuz Im using organic nutes. I think Ima stop trying to reinvent shit and just do a res change when the plants look stressed for no other obvious reason.

I noticed what was said about H2O2 earlier, I cant use H202 cuz Im using organic nutes. I think Ima stop trying to reinvent shit and just do a res change when the plants look stressed for no other obvious reason.

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Good call,

The only time I had root rot problems was from using too many organics with small root systems... small root systems cannot handle a reservoir full of organics and get overwhelmed, especially in warm conditions. Once they were a bit larger though, introduced myco and organics and I only *changed* the res once during flower, and it was due to a mistake not a necessity. Merely added water with a variety of nutrients.