Rockwool runoff is at 7! Feeding @ 5.8ph

Hashrosindabs · Mar 7, 2021

Hey there my 4x8 tent, using two 4x4 flood tables, irrigating using floraflex top feed to waste. My temp is 82 in day and 73 at night. Steady 60-65 RH.
Currently in week 3 of veg (was going to flip but having some issues) in a sea of green. 24 6” Hugo blocks per light. Feeding for about 35 secs at a time which is about 100ml. Aiming for 3% shots.
Drybacks over night is at about 50-55% by the time my lights turn on. Currently 6 shots a day, last shot @ 9AM and lights off at 11AM. Maximum moisture content is usually 67-73% by my last shot/feed. My ph is at 5.8 and my ppm is 950. Runing athena pro line, with mammoth p, silica and black strap molasses. However my runoff has been coming out at 7pH the past 2 two days.... plants look healthy, can’t figure out what it is. Flushed them using Athena cleanse and hardly dropped down, 6.8/6.7ph. Any suggestions or ideas as to what I might be having issues with or doing wrong? My reservoir is at 69-71F. Using ac infinity 6” for an exhaust with two oscillating fans and a clip fan. I have good air circulation, pretty dialed in environment. I can’t figure out why or how my ph can be that high.... oh I’m recirculating my reservoir with a water pump, to air-rate it without air pumps to AVOID rising pH... help please

Dirtbag · Mar 7, 2021

Try feeding 5.5 ph and stop giving them molasses and mammoth P. I'd even give a healthy dose of H2O2 to kill off any bacteria in the wool. It's likely bacteria blooms causing the ph drift imho.

Using molasses in a recirculating hydroponic system is asking for problems. Id actually recommend trying a drain to waste approach as well. It's far easier to control.

Hashrosindabs · Mar 7, 2021

I’m draining my run off, just using a recirculating pump to keep my nutrients and water mixed well and aerate a bit. I do have a air pump and air stones but I opted out using a water pump in my reservoir to try and prevent my pH from going up. Appreciate the feed back and the help!

Goodthingsgrow · Mar 7, 2021

Any algae on your cubes?

AZLandshaper · Mar 7, 2021

u using a meter or bromo drops to determine pH?
I like to confirm every few weeks w the bromo drops to make sure my meter is correct.

also could be the water. using tap water?
My tap water requires two doses of acid to settle the pH where needed. 1st application brings it down and the second stabilizes things. I believe most tap water has buffers that counter the acid to a certain molar concentration.

Dub_City405 · Mar 7, 2021

I dont sweat it to much brother. The runoff varries with mine aswell.

When they reaching for Jesus and you pay attention to the input your feeding. And they healthy. I wouldnt worry to much.

Hashrosindabs · Mar 8, 2021

Hey guys thanks for the feedback and the knowledge!
I have a slight bit of algae on a couple of my cubes, just on the top (only on the 2” rockwool cubes) they didn’t get any algae on theHugo blocks cus I have floraflex caps on them. Which protects MOST of the light.
i use blue labs ph and ec combo meter and I use RO water as well.
I can’t get the ph to drop down... I’ve fed them at 5.2ph and even overwatered to get about 30% flush and they still won’t level out

got the runoff stuck at 7pH and it’s driving me crazy.
Also I was examining the garden, and I decided to pick up cubes to make sure everyone has even water, and even checked the roots...I have some roots, but they seem to have slowed down and aren’t growing so aggressively any more...
I also noticed little white dots, that disappear when I touch them and I couldn’t figure out if it’s beginning stages of mold or PM, or if it’s just salt build up being flushed out?
RH is at 60-65, day temp 77-80F and night temps are 67-70F.
My reservoir is at 68-71F and I have plenty of air circulation and exhaust... any tips or clues as to how to fix my issues would be much appreciated

Hashrosindabs · Mar 8, 2021

Some pics of u guys can help me out

Wh1teScorp1on · Mar 8, 2021

Shouldn’t roots be a lot larger? I’d think maybe overwatering causing roots to not search for water. Try playing with your water cycle. Never used those large cubes or slabs but I figure your too wet. Could be wrong

Wh1teScorp1on · Mar 8, 2021

That definitely the start of mould too

Hashrosindabs · Mar 8, 2021

Damn... is it really mold and not salts?! I have a couple 4” rockwool cubes cus I had some extra cuts left... but they’re fully rooted and get watered a lot less cus I hand water those. Mold and not salt build up getting flushed?! Why on the bottom of the cubes and not anywhere else? Would it be cus, like u said my cubes are too wet causing not only beginning stages of mold but for the roots to not be growing as rapidly as my 4” cubes?