DWC rising ppm?

[nibec]

looking for some suggestions from some dwc growers here!

i did a res change last week. and started the plant at 520ppm. - 5.5ph.

now. what has me wondering, is my ph over 24 hours will jump from 5.5 to 6.0

ok maybe thats not so drastic, however, my ppm, over the past 6 days has been as follows

520
500
520
520
530
530

i top up with plain RO water daily. is it maybe my ph down that i use every day thats keeping my ppm jumped up there? if so.. why is my ph jumping so fast?

i use advanced nutrients 3 part, and benny tea.

the tea jumps up my ph a little, but i only add it every few days. so, i dont understand why all of a sudden lately im having to add about half a ml of ph down daily.

there is no slime that i know of. and the plant is growing great now, and the root system is developing nicely.

shes about 8.5 inches tall, but nice and bushy, 6 tops on her (FIM'd her a while back) and showing zero stress.

new to dwc, so, maybe this is just a basic question. i just want to get the rest of my kinks worked out before i start weaving her into my screen, as it will make it a lot harder to to pull everything apart to get in there and look (still have ways to test ph/ppm, and add water + nutes... but, it will be tough to physically look into my res.)

 

[PrairiePoet]

The rise is a bit fast. I usually see that much in two days. What's the pH of the RO you are topping off with (can't think of what that is right off unadulterated), and are you checking before or after topping off? And how much are you needing to top off with and how large a reservoir?

If you're not seeing stress, hard to say what is the cause. But I would be wondering and trying to figure it out too.

 

[nibec]

well prairie, i think i might have come across my issue with the rising ppm at least.

to answer your question. i dont know the ph of the RO water, i'v always found testing RO water with a ppm of 0 will kill the ph pens, and never give a stable reading. plus, in theory, a water with 0ppm, should always be a perfect neutral. and even if it has a slight ppm, the water you are adding it to, will influence it to be the same PH, as the res.

im testing my ppm, after adding RO water.

i top up daily, but shes drinking about a gallon per week. , and i keep my res topped to the 5 gallon mark.

anyways, my theory.

i think i have at some point contaminated my ph down with nutes. as, really, ph down should not have a ppm, or if it does, really low.

however i find if i add 10 drops of ph down to a glass (about 2 cups) of water, my ppm jumps up 600.

i dont know where, or how that could have happened, but it is the only logical solution to me. which would also explain why im having to add more ph down than normal to get my ph to drop like it used to. a few drops used to do it before, and now it seems to need upwards of 10-15.

im going to head out today, and get some new ph down, and restock my calibration solutions so i can make some confirmations on this.

the plants are still growing great, and with the new air stones i added (old ones were clogging.. and i was skimpy on replacing them as they cost $12 a piece... but i recently found some that seem to work better (but cheaper buillt.. so i have to be carefull with them, as they are fragile, for 2.50 each!) the roots seem to be growing even faster, and loving it even more! poor things were hungry for air.

ill give an update once i get off my lazy ass and get to the hydro store to pick up my items.

 

[nibec]

well, got some new ph down, same problem. so i know its not contaminated. but i still think its the ph down.

my ph is rising too fast, and my ph down is adding ppm to the water, faster than my plant can eat its nutes. SO...

this gives me reason to believe something is in my res... (even though i'v cleaned/bleached etc it 2 times in the past week..)

from what i understand, as the plant eats, the ph should rise, so, if its eating very little, the ph should only rise very little, thus, i shouldnt have to ph down it as much as i am. maybe once every 2-3 days.. instead of the current daily adjustment.

im going to step back from giving it ph down, and see how the ph reacts to it.. maybe some experienced dwc people might be able to get more of an idea from that..

i would suspect, if there is something else in the res, that the ppm should just keep rising, up past 7, and eventually 8. (if it hits 6.8-7, im lowering it right away)

however, the ph always has been returning to 6.0 or 6.1 .. so.. if it hits there, and stays there, im lost.

 

[nibec]

well, instead of knocking down to 5.5, i did 5.8 ... and the same 24 hour time frame, shes sitting 6.1 again..

so im going to leave her there another 24 hours... and just see what happens.

any ideas so far? anyone? lol