Leaves of seedlings turning yellowish with whitish spots


Excellent! I have the same one as @Lornakins but mine tested exactly 1500 when I did the 1500 test so I didn’t worry about it.

My directions only say that we should calibrate it and that it was factory tested and is accurate, but that it may need to be re-calibrated. But it does not say how.

I will look online and see if I can find anything. But yeah I agree she should test again. @Majiktoker


Ok, thanks! :slight_smile:


There are calibration instructions above for both of you @bob31 and @Lornakins


ok, there is a very small hole on the back. Gonna shine a light in there and see if there is a trimmer screw inside.


If so that’s your calibration screw but they are extremely sensitive @Lornakins my pleasure


Since mine is accurate, I’m not gonna fool with it. But there is what looks like a screw in there to adjust. Very hard to see, but that has to be it.

small hole above clip in the rear


Yes sir I believe that’s it :+1:


Yes, it is very difficult to see it and get the screwdriver in it right.
@Majiktoker It really is sensitive and the closest I could get it was 1510. I guess that’s close enough.
Now, what ppm should my water read that I am using to water them after adjusting the PH to 5.4?


Roughly 3-500 ppm if possible


The PH adjusted water going in is 011 (no X10 blinking) and the runoff is 063 (no X10 blinking)


Wow that’s really low that could be what’s going on with them


So what should I do? The FF Grow Big that I bought is the green label so I’ve ordered the blue label and it won’t be delivered until the 31st.


Do you have any cal mag? They will bring your readings up a little Atleast certainly to a healthier range

If you have cal mag add a tsp or however much it takes to Atleast get it to 1-300 just dont go over a tblsp for each one or the one however many are having the problem and they should bounce back im almost 90% sure that’s what’s going on


I don’t have any cal mag. Is there any kind of common household thing I could use until I get some? I have compost that I get from the garden center and I have worm castings. I could grind up some egg shells for the calcium. There must be something I could do… :worried:

I have some epsom salts.


Epsom salt will work 1/2 tsp per gallon of water usually, however at their size I would do a 1/4 tsp per gallon of water…there is always something that can be done :slight_smile:


Ok, thanks. I will add 1/4 tsp to my gallon of PH adjusted water. :slight_smile:

I put 1/4 tsp in my gallon of water and it brought it up to 186 ppm on the TDS meter. @Majiktoker
@BIGE I don’t see @Donaldj on here.


what kind of coco coir @Lornakins i use sunshine #4,and promix which contains dolemite lime. this will give you a 6.5 ph even if you put 5.0 ph water in it,i’ve tried… anyway i quit fighting the ph and done what @Donaldj said and that is to raise my ph… i did not have troubles then or now so all is good here… don knows his stuff, and i’m sure he will not mind elaborating on this issue as well as the others who are helping out…
do not get discouraged lorna, we all have problems of some form or another…happy growing!


Keep me posted


What I used is in the pic at the top of this post. I don’t think it has anything in it but coco coir.


After using the epsom water at 186 ppm, the runoff is now at 124ppm. I sure hope they start recovering now. :relieved: