using a bunch of ph down when using tap water?

Banana444

Banana444

Well-Known Member
Just checking to make sure it normal. First time running a rdwc 2 sites with a external res. 40gallons using tap water ph is 7.4 and used a little over a half of the smallest gh ph down bottles to get it down to 6.0 and ran out. I picked up a dry 2#bag of ph down, that should go way farther than the premixed. Is this the norm? I could get an ro system if it is necessar, but from what i have read most that have decent tap water, its easier to use that instead of ro. I have only done dwc once, used ro and cal mag, worked great except for ph was constantly rising.
 
it should be 90 odd percent phosphoric acid, this is the stronger one
you can also buy, 30 odd percent nitric acid but this requires more
some folk like to use the nitric during veg and the phosphoric during flower

the nutes should bring it down from 7.4 to about 6.8 or so when you bring the ec to 1.0
ec at 1.5 it should be about 6.5

if you add the acid at this stage i would of added around 5ml per 50 l res or 3ml per 20 l res

your res is around 150 liter, so you should only need something like 15 ml of phosphoric acid once you have brought the ec to around 1 to 1.5
if the ec is lower than that during early veg .5 - .8 then you could double the amount of phosphoric acid to about 30 ml to get it to 6.0

peace
 
Advanced nutrients...i rechecked my measurements and i used about 5oz of gh ph down to get from 7.4 to 5.7 and the next day it was 6.4 in the am. I am using far less of the AN...and i can tell its more concentrated, be careful using strong acids as we all know. Im using more like 4-8ml to drop the ph half a point in a 40 gal res
 
It has something to do with tap water. I don't know whats in it that the ro filter takes out but I hardly ever, ever, use pH down. Maybe on a real weak nute solution. Probably 99% of the time use pH up. Unless you have real good tap water, which I have never personally seen, I know mine is garbage. I would suggest using ro water.
 
skunkd0c said:
it should be 90 odd percent phosphoric acid, this is the stronger one
Click to expand...

What ones that?

GH liquid http://generalhydroponics.com/site/gh/docs/prod_msds/pHDownLiquid_MSDS.pdf

It also uses citric acid, which IMHO shouldn't be used in hydro.

Usually its bicarbonates in tap water that require ph down. You can get your water tested from a state university for a reasonable fee.

I use RO, to make life easier on a well, but if you water is ok then you don't have to....

- Jiji
 
Its going really well so far. My tap water is 390ppm. 1/4strenght nutes right now in dwc and picked up a chiller last week. Ph has been perfectly stable so far going on 3 days and hasnt changed after res change and adjustments. Good to see your still around @jijiandfarmgang , you are always providing good info. I might pick up an ro system later this year but i keep asking myself why should i if tap water works just as well. I used ro on my first dwc and ph was always drifting up, but i was using gh ph down the whole time.
 
jijiandfarmgang said:
What ones that?
Click to expand...

Every bottle of ph down i have ever seen is phosphoric acid this is the most common
with the exception of nitric acid from canna

citric acid lol

i have noticed over the last few years the hydro shops sell branded ph down from the nute companies or whatever
it used to be just plain phosphoric acid with no fancy label


nitric acid http://www.growland-hydroponics.com/CANNA-pH-Grow-38-Nitric-Acid-1-L 38%

phosphoric acid http://www.growthtechnology.com/product/ph-down/ this one is 81% most of the branded ones seem to be 81% phosphoric now and more expensive

have you had problems purchasing nitric acid or phosphoric acid ?
 
skunkd0c said:
have you had problems purchasing nitric acid or phosphoric acid ?
Click to expand...

Well I live in the middle of nowhere, sometimes I travel and see a hydroponics store. It's like a love hate thing. I hate them and how they are so commercial, but I like to check things out every once and a while.

Any ways, I usually order what I need and I'm super frugal. I found some phosphoric acid thats 85 percent, but never found a decent deal for nitric acid. I thought about going through a local company and chemical supply but never really bothered. I mix my own nutrients and use RO, never use ph down, only a bunch of up.

- Jiji

P.S. I doubt it was even legal to ship phosphoric acid at 85 percent in an unmarked box in the US. But I wouldn't know.
 
Mines 78% phosphoric acid and a few small tiny drop shifts a litre a couple points no problems, seems strange your having to use such a large amount, it dosent take much to start registering on my ppm/ec meter either. My ph up/down are from a company called essentials, burns like crap if you spill some on you.

If i could remember the thread that explains how pure water exists as a vacum, does not conduct electricity and is prone to ph swings id post the link but im all blank, sort of recomends adding a small charge of nutes or calmag to pure water to stabalise it.

My waters under a 100ppm straight from the tap and been fine with it.

:-)
 
Last edited:
jijiandfarmgang said:
Well I live in the middle of nowhere, sometimes I travel and see a hydroponics store. It's like a love hate thing. I hate them and how they are so commercial, but I like to check things out every once and a while.

Any ways, I usually order what I need and I'm super frugal. I found some phosphoric acid thats 85 percent, but never found a decent deal for nitric acid. I thought about going through a local company and chemical supply but never really bothered. I mix my own nutrients and use RO, never use ph down, only a bunch of up.

- Jiji

P.S. I doubt it was even legal to ship phosphoric acid at 85 percent in an unmarked box in the US. But I wouldn't know.
Click to expand...

The law on these things is ridiculous , if i were to try and buy any of these things from a pharmacist/chemist they would look at me like a terrorist of some kind
although any builders merchants sell all of these things
even supermarkets have started selling sulfuric acid 90% in the plumbing section

the 30% nitric from canna is like 3 times the price
and you need a lot more nitric @ 30% to lower ph

i am sure the old plain bottle phosphoric acid was in the 90 percent range
i hardly ever use the stuff a 250ml bottle last me years
my tap water is good and the nutes take care of the ph for the most part

peace
 
I went from using 6oz to lower ph from 7.4 to only 6.4, then ran out of GH ph down, to advanced's ph down only took about 50ml to lower frm 7.4 to 5.8 and has been stable for over 4 days. Also advanced didnt raise ppm as much as the GH ph down?
 
Banana444 said:
Just checking to make sure it normal. First time running a rdwc 2 sites with a external res. 40gallons using tap water ph is 7.4 and used a little over a half of the smallest gh ph down bottles to get it down to 6.0 and ran out. I picked up a dry 2#bag of ph down, that should go way farther than the premixed. Is this the norm? I could get an ro system if it is necessar, but from what i have read most that have decent tap water, its easier to use that instead of ro. I have only done dwc once, used ro and cal mag, worked great except for ph was constantly rising.
Click to expand...
I tried to use PH down with my tap water and it would go back up by the next day. A RIU member told me that tap water cannot have the ph level lowered. I decided to get a 5 stage reverse osmosis system. Quite a few parts and setup but hopefully this will fix my ph problem.
 
Banana444 said:
Advanced nutrients...i rechecked my measurements and i used about 5oz of gh ph down to get from 7.4 to 5.7 and the next day it was 6.4 in the am. I am using far less of the AN...and i can tell its more concentrated, be careful using strong acids as we all know. Im using more like 4-8ml to drop the ph half a point in a 40 gal res
Click to expand...
Are you using tap water?
 
I am having no issues. Ph has been stable over a week. Obviously tap water varies across the country. Mine sits in limestone and has high cal and high ppm and ph about 7.4. Also what brand of ph down? Gh ph down didnt work at all. Needed a higher concentrate and im golden...i also got gh hardwater micro to help with the hardwater.
 
Banana444 said:
I am having no issues. Ph has been stable over a week. Obviously tap water varies across the country. Mine sits in limestone and has high cal and high ppm and ph about 7.4. Also what brand of ph down? Gh ph down didnt work at all. Needed a higher concentrate and im golden...i also got gh hardwater micro to help with the hardwater.
Click to expand...
I used a great amount of ph down in 10 gallons and it went down for a period but came right back up. Now I am going with all RO water. Well, next round at least. Waiting for parts. Setting up a RO system is more challenging then one would think.
 

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