How fast does nute burn show up?

[Observer Tom]

Hi guys, second time hydro grower here looking for some info. I'll fill out the hydro form below but here's the situation:

My clones are about two/three weeks old and went into the net pots about a week ago. Roots are showing out the bottoms on most of them and I'm starting to see new growth up top. My PH has been between 5.5 and 6.0 and the EC's have been slowly dropping from around 1.8 when I first put them in down to about 1.35 last night. I keep a daily log to watch changes.

My PH has been rising about 1-2 points per day so I've been using a lot of PH down and the res was starting to get a buildup around the edges, so this morning I rinsed it out and put new tap/well water and nutes in.

I used 5 tbsps GH micro/bloom/grow for one of those black 25 or 30 gallon concrete mixing tubs from home depot. Well below the recommended amount on the bottle for vegetative growth.

My EC came out to about 1.9/2.0 which is around 1330/1400 if I'm doing the conversion correctly (x700).That seemed pretty high but I figured maybe I was doing the conversion wrong.

Anyway I went to work and when I came home for lunch I noticed some mild burning and tip curl. I emptied about half the res and refilled with water bringing the EC to 1.10, then I top fed all the plants to rinse out the stronger solution.

I believe I have taken steps to correct the issue but I wanted to find out if the timeline sounds right. If you think I should do something besides reducing the EC and flushing please let me know. The roots look white and healthy so far.

Is 6-8 hours long enough for nute burn damage to become visible?

Am I converting the EC correctly? I looked up my model and it said x700 which makes sense except how high my readings are with that little amount of nutes.

Here are pics:

What STRAIN are you growing? Blackcherry.
What was the establishing technique? (Were the seed or clone?) Clones.
What is the age of your plants? 2-3 weeks from cuttings.
What PHASE are the plants in? (seedling, vegetative or flower) are the plants in? Seedling / Vegetative.
What Technique are you using? Top feeding via buckets.
What substrate/medium are you using?(Hydroton, RockWool etc.) Hydroton.
What is the Nutrient temperature? Unknown, best guess 60f.
What Nutrient's are you using? GH.
What is the TDS/EC/PPM you are using? Hanna EC/PH combo meter with sunleaves PH drops to confirm.
What is the pH of the "Tank"? 5.5-6.0.
Are you sure your calibration is correct on your equiptment? Yes, confirmed with sunleaves PH drops.
When was your last watering? 3x / day hand top watered.
When was your last feeding change? (ie. grow-bloom-micro-additional) Changed res this morning 1 tbsp g/b/m per 25-30 gallons.
What size bulb are you using? 4x 1k MH.
What is the distance to the canopy? 2-2.5 ft.
What is your RH Factor? Unknown.
What is the canopy temperature? Unknown, comfortable/cool to me.
What is the Day/Night Temp? (Include flucutaion range) Unknown, comfortable to cool to me.
What is the current Air Flow? (cfm etc.) Large room, standing fan, open door.
Is the fan blowing directly at plants? Oscillating on low setting over them.
Is your water HARD or SOFT? Well water, probably hard.
Has plant been recently pruned, cloned off of or pinched? No.
Have any pest chemicals been used? If so, What and When? Mild solution of florimite on several test plants 3 days ago.
Are plant's infected with pest's? None that I can find.

 

[Observer Tom]

This is an all-new DIY setup and I washed the new hydroton by filling then dumping from one 20 gallon bucket to another for about 2 hours before using it, but there is still sediment coming off it so I attributed the daily PH rise to that. I'm not sure what else it could be, but if you have any suggestions I'm all ears.

 

[PuReKnOwLeDgE]

You should try about 400-450ppm @ .conversion, will be perfect for the small plants.

.8Ec

 

[Observer Tom]

I just went and looked at the shotglass measuring cup I used this morning, it has tsps on one side and tbsps on the other. I think I may have used the wrong side, giving them 5 tbsps == 15 tsps when I intended to use 5 tsps.

That would certainly explain the higher EC than I expected. I figured I was doing the EC conversion wrong.

Thanks for the tip Pureknowledge, I'll bring it down even a little further. As long as I have the thread open I may as well ask another question:

I've been relying on the room temp to keep my res temps up. I have a chiller but no heater, what's the minimum temp I should allow my res to hit? I've often heard no warmer than 70f, but is that optimum or maximum.

 

[mitchyboy89]

Optimum res temp 60f-75f, 60f allowing the nutrient solution to hold more oxygen. Dont stear towards 85f region, the solution holds little oxygen at 85f and the roots will become easily damaged. Heat damaged roots are very susceptible to rot, wilt and fungas gnat attacks.

Mitch

 

[Observer Tom]

Thanks Mitch. I have a nice chiller on standby but the cold concrete floor and winter temps are doing an excellent job at this time of year. My very first hydro run was lost to root rot so I'm keeping a very close eye on it for this 2nd run. So far all roots I can see are pearly white. I have 6 air stones in the res where the buckets drain back to, so no standing water without aeration.

I figure in a week or so once the roots are more established I should switch them from top feed by hand to either E&F or RDWC. I'm open to suggestions on either method.

Like I said, last time I set up as RDWC and lost it all to rot but I didn't have a chiller and no airstones in the individual buckets, I would definitely fix both those problems this time. It was also summer back then and much colder now.

E&F sounds good to me because it would be easier to set up and I already have 1/2" holes and grommets for all of the buckets. I would want to use 1" at least if I went RDWC and the grommets and plumbing add up.

 

[mitchyboy89]

E&F is the way to go imo my friend

 

[FreezerBoy]

I figured I was doing the EC conversion wrong.

EC is EC and requires no conversion. Your EC is definitely too high for this stage of growth. Get it down to the 0.7-0.8 range

 

[Observer Tom]

I remember finding a post on the Hanna forums saying I should multiply my EC by 700 to find PPM, is that inaccurate?

Any ideas on why my PH rises over time? I'm concerned that by adding so much PH down I may be filling my res with too much of whatever PH down is made of.

I'm not using RO water but I hear I should be. Think that would be a good change?

 

[FreezerBoy]

I remember finding a post on the Hanna forums saying I should multiply my EC by 700 to find PPM, is that inaccurate?

Yes. Hanna uses 500, 640, 650, and 700 and they're all lies. Were I to say 500 and 700 were identical numbers (as does "PPM") would you think me a genius or an idiot? Were I to say 550 is a larger number than 750 (as does "PPM") would you think me brilliant or a moron?

Multiplying EC does NOT equal PPM, it does NOT give Parts Per Million. It simply means you're several hundred times off the truth. You already have the truth right in front of you. EC is EC and requires no conversion.

Recirculating DWC seems to have it's own rules pH wise. Overfeeding as you seem to be I'd have expected pH to be dropping but, you also have plants at different stages, and that could be throwing things off. I'd think those in the back would feed at a completely different rate than the near seedlings up front.

RO is far less pH stable than tap. If your EC is 0.5 or less, you don't really need RO. With well water however, a water test might be advisable.

 

[Observer Tom]

After dumping the res and refilling at .8 EC the PH has become much more stable. Before the flush I would regularly find the res PH at 8+ but now it's low 7's. I've been top feeding by hand so they don't get the higher PH water until I drop it to between 5.6-6.

I knew PPM was pretty much a lie without lab equipment, but there's a lot of advice out there regarding what to do at different stages and being able to convert EC to use that advice is nice.

Thanks again for all the advice everyone. I'm having a good time with this hydro stuff.

 

[Festezio]

Yes. Hanna uses 500, 640, 650, and 700 and they're all lies. Were I to say 500 and 700 were identical numbers (as does "PPM") would you think me a genius or an idiot? Were I to say 550 is a larger number than 750 (as does "PPM") would you think me brilliant or a moron?

Multiplying EC does NOT equal PPM, it does NOT give Parts Per Million. It simply means you're several hundred times off the truth. You already have the truth right in front of you. EC is EC and requires no conversion.quote]

100% CORRECT
I'm a new grower who has invested a large sum of money and time to grow my own medicine. I have been having strange frustrating problems that defy logic since I began. Two days ago I think I figured it out. The entire concept of reading PPM from relatively low cost EC equipment using math calculations based on three different different conversion factors bit me hard in the ass . I have been buying my equipment from a high volumn fairly smart hydro shop in the Pacific North West. They sold me a top of the line combo meter with calibration solution and showed me what to do. Unfortunately they along with90% of the shop owners I have talked to dont understand what they are telling people to do. For 5 months I have been under ferting bad. I will detail everything that happened and what I have learned about how bad this problem is in my sick plant thread.
Stop the PPM madness learn simple math and go EC