Issues following flush - pH DOWN DOWN DOWN

Hey GC

So hydro have been incredibly fun to mess around with, up till now : I've hit a problem I can't fix.

Following some high pH issues I ran a flush a couple weeks ago to change out the system. Following that was added in RO water with nutes pHed to 5.5. Since then I've been topping off with 200 ppms tap, mixed with nutes prior to adding. Once I had to do some playing around with pH down was done to bring the res from 6.5 to 5.5(ppms were at 1100 already) once - no idea how it shot up.

Now the problems :

The pH keeps jumping down to 4.0 as water levels drop. I refill with dechlorinated tap(pH 7.5), no nutes, and ppms rise to 4.2-4.4, ppms 800. Then I adjust with pH up to bring it between 5.3-5.6.

The next refill pH is back LOW; this has been happening the last 3 times with nutes kept at 600-800 instead of 1100 ppms.

What can cause sudden reservoir acidification? Could it be the EWC tea I add a cup or two of every 2-3 days? But its pH is at 6.1-6.3 on addition.

Could the one addition of pH down I did have screwed everything up since the last flush? (it should be neutralized by the many additions of pH up so far..)

Summed info:
Ran a flush
Filled RO + nutes : pH 5.5
Fixed pH issue 6.5 with pH down week after flush
cup of EWC tea every 3-5 days added.
Top off res with 200ppm tap and 700 ppm nutes pH 5.5-5.8 - use flora nova bloom
Now pH shoots downwards before every refill to 4.0, battling with pH up and alkaline tap water, 3 fills later its still an issue.

Thoughts?

Edited by 1sttimegrower, 26 May 2012 - 10:16 PM.

Hmmm... I have read big PH swings can be caused by your plants being hungry for specific nutes that they have consumed first causing what is left over to cause the PH swing. Maybe add some floralicious plus to the res as a nute boost and bump your PPM's back up if the plants were thriving at that level.

My systems PH slowly increases between res changes (weekly) but only moves from ~5.6 to around 6.5 during that time so I leave it alone and have no issues. I add only tap water daily to keep the res from drying out and empty and refill with fresh nutes weekly.

Did you flush the plants when you flushed the res? If not you will run low PH stuff back into your res from the medium the plants are in.

I did flush the plants; it was a system flush where I first ran sledgehammer through followed by 3 drains and fills or fresh water.

The raising pH I understand; as nutes(acids) are used, the pH rises. But I didn't think it can cause downward swings? unless some acid is in excess; no idea WHAT though! I run lucas 4/8/7 and the plants are transitioning from flower back into vege (they veged, then flowered, and now have flipped back, after putting them under the sun)..

I think if the problem stays tomorrow I'll change the water out; its been 3 weeks since the last change. However, before this bull, I was good with a 2 months lapse between changing out the water and the plants grew like mad.

They're growing, slowly, but the pH changes are really taking their toll - the blue dream is showing N and P deficient leaves while the tangerine dream has pH flux spots.

The only difference between now and the two month period, is I'm refilling with tap water rather than distilled - buying distilled for outdoor hydro is crazy expensive. Don't see how that can cause the swing DOWNWARDS though, as the tap is a pH is 7.5...

edit: might just be with tap water I need to periodically change the res - just occured to me that the tap salts are probably building and messing with nutes whereas the distilled didn't. At least now the submersible pump I added in will be put to good use (before I relied on a weak zippo-sized pump which broke; now I got my 264gph hooked up to a T - one going to the buckets one just shooting at the wall aerating the water)

Edited by 1sttimegrower, 27 May 2012 - 03:08 AM.

Ya...my tapwater is about 20 ppm and neutral so I dont have those issues. Did you check res PH before and after adding water? Might be an indicator that its the water. You did mention PH dropped as the levels dropped so sounds like you did.
G/L

yup; res before 4.0 today, after adding tap water with 1/2 strength nutes (ph at 6.8) it hit a pH pf 4.3. pH up'd to 5.5. Checking their pH now and its at 5.4; looks like tomorrow it'll be back down.

Guess I need a res change

What is the time of the Plants ? I cannot see how old they are ? Are you flushing because you are finishing ?

Flushing because I flush every now and then; I use tap water and the 200 ppms salts build up quite a bit. They're not flushing to be picked; I want them to vege more actually.

Flushing because I flush every now and then; I use tap water and the 200 ppms salts build up quite a bit. They're not flushing to be picked; I want them to vege more actually.

Did you calibrate your meters ?

Meters are fine; just recently swapped the TDS meter out because my old one stopped working. The pH meter is working fine as my tap water is measuring like it always does.

Add Pro-Tekt or Potassium Silicate to your Rez. The Silica will raise that PH and keep it higher rather than lower. In addition plant benefits huge time from Silica.

I'll give it a go next time the pH is swinging down like that; Thanks! Right now though my pH down doesn't seem to want to lower the pH by much; pH is at 6.5. But the plants are happy, and roots are white (trimmed them to try and stimulate re-vege, new roots are happy) so i'm not too worried. Jeez, I go months without issues and happy plants to issues without any idea why. I think my tea's might be the issue here... dunno why they'd stop working so well though

I had that problem and I switched to distiled water. I only add nutes when I change my res once a week. I top off with plain distiled water in the middle of the week. the distiled ph is 6.5 when I add nutes it goes to 4.0 I ph up once to 5.8
on the 3rd day the ppms are high and the ph is a little low I add the distiled water and it goes right back to 5.8