First Hydro grow already hate PH!!!!

Hey Guys,

I have been having issues for a week now with my PH rising each day from 5.5 to 6.6-6.8 this is city tap water, that i have been ph downing to 5.5 from 7.2-7.5 out of the tap. No nutrients have been used yet just water as they just have the second set of leaves staring.
They are seedlings I germinated in papertowel on may 15th, they had the starter leaves and one set started along wiht a tap root out of the small rockwool cube i used when i dropped them in the hydro on may 21st. Seem to be coming along slowly but no issues so far other then having to adjust my PH daily! I start at 5.5 and by the end of the day its at 6.5 if i leave it till morning its above 7.
I am using a 400watt HPS, room is 75-76 during the day (76 by light out time)
I have 2 Automara II, and one Sensi Star. First grow will determin the winning strain to keep!! LOL
I have three plants all using a Single Shot Garden, its a mix of drip and DWC, water stays steady at 68 (i understand thats decent, stay under 70) and I have air pumps with stones in the bucket.
After a week of frustration trying to keep my PH right in these three buckets (hard to adjust with out just changing the water....) I think I found my issue.
I got a nutriidrip tri meter as the PH liquid test unit would not give me accurate numbers (the numbers above are what i tested with the current water over the last few days with the new meter).
So far i can see the plants are starting to grow faster, now that i can keep PH in check with constant monitoring! and speding $200 on a real meter! the liquid test is just no good for a stoner thats color blind half the time LOL


I was drinking some water from my britta filtered unit and thought i should test the water im drinking with this meter to see how clean it is......(of couse i just smoked one but i seem to get great ideas when im stoned!!)

Tap - 7.2 PH, 220-230 PPM
Britta filered water - 6.0PH 130-140 PPM

This inspired me to filter my water so i sat there stoned filtering 30L of water lol talk about a cheap way to filter the water fairly decently!

Guess what........ PH is stable now!!! Lowered it to 5.7 and its gone to 5.8 and holding for a full day!

PH is so important yet such a pain in the you know what to deal with! (well with my system anyway)

I would love to try the aero system Stinkbud has on here (Harvest a Pound Every Three Weeks!) but im only using a small closet (5ftX2ftX8ft) Been thinking on how i could modify his system to go smaller for my closet that way I have a res to deal with, not three different buckets!

Anyway any new growers trying hydro with city waters make sure to test your water and try a cheap filter, it seems to make a big difference!

Once my plants dont look like tiny specs I put up some pictures of my setup....

Any input or advice appreciated!

Wow, I see you're having a bit of a time with this. I know its good practice to maintain pH but just the same you should also use distilled over tap. The chlorine added to tap water could also mess up your crop just the same. I do want to see if I get a difference out of filtering city water but a couple gallons of distilled water wont cost you more than $5.

also presoak in ph'd water what ever kind of medium your putting in the net pots for like 2 days the bigger container the less your ph will climb as the plant drinks and dont eat = this makes the ph swing too ,I use hydroton and them damn f#$$@ing rocks raised mine till i thought about it after a bowl one night as i was stumped well its about learning from each past grow and using that info gained in the next !!!!!! happy growing

yeah hydroton will increase ph like crazy when its new. also u will find your ph is more stable once u get nutes going as they have ph buffers built in

Yep I did Pre soak my cubes for a day in 5.5 PH water prior to using them so this should not be what was causing the rise, but who knows.... it has stopped now but I am not sure if thats all the lime from the cubes are gone or if its the filtered water. I figure if I wont drink tap water with out filtering it why should my plants!

I do know after filtering my water with a britta and watching it for 3 days not its only gone up 0.1 so I am thinking it was something in the water that was causing this rise.

Just got home and things are looking great today! noticable growth during the 8 hour work day, going to do a water change tomorrow and start adding nutes. I am going to go about mid way with the nutes, it says for seedlings to use 3ml per L of water so I am going to go by that even though they are not seedlings any more now that they have a couple sets of leaves, just figure best to start out light and work my way up to a full dose of nutes. If adding nutes makes teh PH more stable thats great news!

Thanks for the input guys!

The problem is because you're using tap water. Tap water contains Carbonate, aka hardness. This carbonate acts as a buffer to keep the pH around neutral. If you want more explanation I can give it. I was using tons of pH down everyday until I switched to RO water.

Once using RO water, I don't have to adjust the pH at all. It stays at 5.8 for 2 weeks straight.

his problem may not be the tap water, its lack of nutes to keep it stable. ph only affects nute uptake, thus, seeds and clones need not worry about ph. water is water, without nutes what are the getting? water. when nutes are added it should lower the ph, mine goes from 7.1 to 5.5 after i reach my nute levels. again, dont waste time and adjusters on just water. i know somebody will say something about rockwool or coco needing certain ph, that is not what im talking about

sorry guys im just gonna jump in and ask probably a really daft question and it saves a whole new thread. Im a little new to hydro.
From reading the posts above am i right in my assumption, When refilling my res its better to put my nutes before testing and adjusting ph?
Once again apologies for the hijack

water, nutes, additives, then adjust ph. in that order.

Thanks man i did try finding the answer but everybody is far to busy trying to sell ph kits and show you how to adjust tap water.
Right im off to adjust
Thanks again!!