Ongoing problem with deficiencies at around 30 days, hard water problems.

[Tanglefoot]

Every auto grow I get yellowing & what looks like mg deficiencies at around 30 days on multiple different strains. Am in soil & under COB & LED. PH, temps & RH are good.

I've tried increasing base nutes. Decreasing base nutes. Adding cal/mag. Moving the lights up a bit. However it's the same every time. After about day 45 they always seem to recover but always the end result is affected.

I have very hard water here (about 500 EC) & was reading that perhaps I should try adding epsom salts as the hard water probably contains a lot more calcium & lacks mg.

Any educated thoughts on this from you master growers would be great ?

Thanks

 

[Renaissance Redneck]

It sounds like you're on top of it, but a couple of questions:
What is your soil mix, just how high are your lights (especially the LED's) and how are you measuring pH?
When do you start feeding CaMg and what rate? I haven't used either light source, but know LED's can really sap a plant.

 

[nizmoKush]

any pictures man?

 

[Waira]

Ray-ed, Niz' what's good my friends? .............. Tangle, just how hard is the water? If it's brutal EC/ppms, cumulative inputs of the minerals (mainly CaCO3) can start to screw up pH, cause ion overload in the soil, both of which can mess with Mg uptake,... adding the Ca-Mg to it will magnify the problem faster and worse!

 

[Tanglefoot]

I use this method for PH but am possibly not doing it right - https://www.autoflower.org/threads/improved-runoff-method-for-testing-soil-ph.42037/
I don't have £$£$ for a decent soil probe. However have looked for accurate 8 but can't find one in the UK.

Soil is Plagron lightmix. Nutes are AN Sensi PH perfect & I use Tangs feeding schedule. Pots are 10L airpots. Water out the tap is around EC 500/PH 8

Lights are at about 18", however they are not very powerful as am only running them on a low power driver. Total power draw is only around 200w.

Yes I did read somewhere that adding cal/mag will only compound the problem which makes sense.

No pics as I am trying to anticipate & prevent it from happening this time round.

Just to add as well, I have also tried flushing through with 3x pot size at around day 30, again this makes no difference.

With all this in mind would you advise adding epsom salts ?

Thanks for the replies guys, much appreciated

 

[Waira]

..gotta get the total ppm's down,... on that EC, do you mean 500ppm from a TDS meter/? I'd look into using RO/Di water, as is or blend with tap to get about 120ppm,...

 

[Yeatster]

I would like to see pics too. I've had, what sounds lik, the same. Can't be sure without pics.
Since I've moved ie, different water source + addition of Epson salt = problem solved. So far...

 

[Tanglefoot]

..gotta get the total ppm's down,... on that EC, do you mean 500ppm from a TDS meter/? I'd look into using RO/Di water, as is or blend with tap to get about 120ppm,...

Yeah sorry I meant 0.5 EC. Maybe ill think about RO water as a last resort but seems a bit of an expensive faf right now, I like to keep things as simple as poss.

I think epsom salts would be a good thing to try then - what do you think Waira ?

 

[Tanglefoot]

I would like to see pics too. I've had, what sounds lik, the same. Can't be sure without pics.
Since I've moved ie, different water source + addition of Epson salt = problem solved. So far...

Interesting thanks, I don't have pics however.


Seems epsom salts are defo something to try

 

[Sage]

If you're in the UK go to your local water board's website and they will have an analysis of the water. I was having similar problems, turns out my water has a shit ton of calcium and virtually no magnesium... I'm my case magnesium foliar spray worked to clear the deficiency, but I stumped up for a decent RO filter for the next grow. Good luck!