PH Levels

What is the acceptable PH range in Hydro?

Searching PH gives me no results...

I should mention that I am at very early veg. Clones just rooted and were put in the bubbler last night.

I am currently at PH of 6.4

5.8 to 6.2 is good for me. Temps between 65 and 80F. :)

keep your p.h between 5.8-6.0 never let it get above 6.0 :thumbsup:

so with only a few drops of PH down I am now at 5.6
I will take a test in an hour and see if it is stable there.

Other than 5.8 what else pertains to PH levels and adjustment.

Example, are nutrients added to water then the solution is tested and PH down added accordingly? Or do you adjust the water first and then add nutes?

Water/Nutes/pH

Some nutes are slightly acidic, others slightly basic.. So you always want to adjust AFTER adding nutes.

Yep.....ph last....always. Before ANYTHING touches your precious hydro babies you should know the ph. And it WILL change......warmer water, different day, the way the plant grows......so check and adjust it often. It's worth the effort for sure. :)

what I am going through right now is I can't get it to stay at 5.8

Keeps rising to 6.3

I have a 5 gallon "resevoir" and add only a few drops of PH down.
If i add more than a few drops it sinks to 3.2 and if I add baking soda it goes back up to 6.4 etc.

I am constantly adjusting, but I am adjusting in the resevoir rather than making new water each time.
Is this OK?

Is there a set amount that will drop my ph 1 point in 1 gallon.
i.e. 2mL of 85% phosphuric acid will lower PH by 1 point?

I have figured out that 15mL or one tbsp will raise PH 3 points in 12 Litres or 3 gallons.

I am new to this hydro thing and quite confused.

having said that, the roots are longer than two days ago and the tops are showing new growth.

It takes awhile to get the hang of how much to adjust "how much". Then things change as your supplies get older and take more to do the same job. In other words...no...there is no set amount; it depends on tons of factors and those factors change all the time. There's a chart around somewhere........I think Dutch pimp has a chart for hydro ph.....but if your medium, nutes, and water are all stable then your ph should stay pretty stable as well.

And ranting further......adding ph up and down DOES add ppms to your solution so IMO you can use too much of one or the other (or both as you go back and forth)and get your true nute ratios out of balance. This is one reason you should change your res at least once a week.....to rebalance ratios and ppms.

NO baking soda! (sodium bicarb) Sodium bad!
Use pH up (potassium hydroxide). Potassium good!

Do you have untreated hydroton or RW in your system? that's usually the culprit, and it's not anything to get overly worried about.
Add your pH down slowly and set to 5.8; if it swings back up just set it back down. It should stabilize and require less fidgeting once the system and media equilibrate.

I will continue to experiment.
I slightly remember ph from grade 10 chemistry but need some more practice. I was into other chemicals at that age...

By the time I get this thing balanced it will be time to change the res...

thanks for the sodium tip.

now further on ph levels, if I am adding up or down to my res and the bubbler is on, does the additive actually mix well with the whole solution? Or, does it merely "float" on the top of the water and evaporate quickly?

so in taking a ph reading, I am only reading the top portion of the solution and not getting an accurate reading.

should I be stirring and take a reading 5 minutes later?

The bubbles will stir the solution. The water that is pushed to the top by bubbles is replaced by water that is pulled down from the surface to give it more water to push to the surface again.

thanks for all the info.

Picking up PH up today and the ph has stabalized after three days at 5.4. I won't touch it until I change the res.

Added some botanicare grow today at 12mL for the 4 gallons which I am hoping will give the the .3 up that I want.


Can someone explain the 10x rule. When lowering or raising PH I need 10x the additive to raise the ph by the second point. i.e raising for 4-5 requires x, raising 4-6 requires 10x.

You aren't going to be able to say the X drops of ph up or down will change the solution X amount. it's not algebra blink.....they are living plants and each one is a bit different. Think of it has having a couple children...they're ALL going to be different from each other and act a bit differently accordingly.
You may be able to feed both kids the exact same thing (and I mean EXACT) but they will respond differently. So do plants.

The only real way to do it is with a dropper, your ph adjuster, and a good, accurate meter. The amount of nutes in your system will also affect ph, as will the amount of 02 in your water (raises ph) so you just don't get to preplan some stuff like how much ph up or down you will need.

Hydro should IDEALLY be checked twice a day but can get by on once a day if the system is stable.

One last thing....almost ALL hydro nutes LOWER ph.....if you added some grow your ph is most likely LOWER now than it was so check ph OFTEN.

i use aluminum sulfate to lower pH... like 1/4 tsp or something gets its about right in a 3 gal res for me.. but i mean add al ittle let it mix and dissolve before adding more. I tried pH down but it took like 20 drops to lower pH by 0.1 and did not stabalize really.

if I add 4 drops of PH down to a 5 gallon res it lowers the PH by 1.0.

What were you using?

It was some aquarium pH down stuff so maybe with nutes it didnt work. Active ingredient was sufuric acid.