It looks hungry to me, what EC are you feeding?
Potassium deficiency can show up as spotting and bronzing of the leaves. Adding magnesium could potentially make things worse as excessive mag inhibits potassium availability and vice versa.

This post was edited by hex2006 on Thu, May 22, 14 at 10:30

Thanks hex

I was trying to keep my ppm at 800 ish as this is for starts, but one week it was 800 next 260 about 150 of that is from the water.

I added cal nitrate masterblend and mag sulfate at a 50% ratio it brought the ppm up to 400 ish. Expected a bit more than that. 7.5 ish ph

I know the nutes were low. My issue now is add more to bring up the ppm or not. Start over? Really not sure what to do.
I could use a lesson in EC use. I don't really understand what an EC meter tells me.

Thanks hex.

Hi Rio,
Ec is universal so the EC reading on one meter is the same as any other. PPM comparisons are more tricky as the meter converts EC to ppm using a conversion factor, depending on the meter 1.0 EC can be 500ppm,700ppm or a host of others. Using EC, 1.0 EC is 1.0 EC.
I would aim for an EC of 1.5 - 2.0 and a PH ideally 5.8, but no higher than 6.3 or you could run into issues with iron (EDTA), unless the nutes use Fe-DTPA or EDDHA.
For plants at that stage i use N 275, P:39, K:400, Mg 54, Ca: 240. The basic solution is around EC 2.5 which is diluted with RO to a level the plants are happy with. The elemental ratio`s arent affected, just the nutrient strength. .

I agree with Hex I stick to EC and not ppm , keep it simple

I will have an EC meter ordered before bed time.thanks!

I use EC for mixing nutes and ppm for tracking subtle nute changes, 1ppm resolution is more useful than 0.1 EC for that job.

Well heck that won't be here till middle of next week. So in the mean time knowing what I have used what is the best course of action until it arrives?

If you know the conversion factor for your meter you can soon figure out the ec from the ppm.

Its hard to find guaranteed analysis info for the masterblend which would help.
Looking at the masterblend 4-18-38 mixing recommendations of using 12g calcium nitrate and 6g mag sulphate per 5 gal those amounts will give you N:75, Ca: 107, Mg:31 and S: 41 with an approx EC: 0.7
The recommended 12g of masterblend that goes with them wouldnt provide any calcium so the source water would have to supply the rest, which would be 130ppm or so in the case of my 240ppm baseline.

This post was edited by hex2006 on Fri, May 23, 14 at 7:51

That is the ratio I use to mix mine. This is a 200 gallon resivour. I mixed based on 100 gal and intend to adjust further. When I have fresh water I mix full amount, at once, but beings I am adding to previously mixed nutrient I am hesitant.

Not sure if this is the same as masterblend
http://www.hydro-gardens.com/41838.htm
but if it is i`d try 12g of the base nute, 10g magnesium sulphate (epsom) 10g potassium nitrate (KNO3) and 28g calcium nitrate per 5 gallons. This mix would approximate what i use, note that it doesnt take account of any elemental contribution from the source water.
Another option is to bump the K a touch and see if the plants improve, 2.4g potassium sulphate per 5 gal will give you an extra ~50ppm. Monitoring the ppm will tell you if the plants are
making use of it. .

That is the same masterblend I use.

If thats the case, the basic 12/12/6 nute mix works out to N: 100, P: 50, K: 200, Mg: 33.5, Ca: 107.
Assuming the source water has a goodly amount of Ca, i`d look at increasing the N and K ppm`s. Using nitric acid for PH control will add some N, where as phosphoric acid will increase the P and 50ppm is already more than enough for toms.

This post was edited by hex2006 on Fri, May 23, 14 at 18:27

Ok, I am using phosphoric acid to adjust ph. Most of the time my ph comes down numerically when I add nutrients but not this time. This rain water wants to be 7-9 ph

9 is high for rain, something probably got into it on the way down or between the collection poin and storage. Ours is normally acidic but it does shift up a point or two when the local farmers are spreading lime on the fields. Did you calibrate your ph meter recently?

No, but confirmed the readings with a solution type ph test. When the rain first goes to the holding tanks it is around 6 but sitting it goes up.

must be coming from the tanks then, if they are made of concrete or have internal cement rendering that would do it,

No, they are a 200 gal food hopper. These were ides in a past life as a bulk container for chicken scraps. Thoroughly cleaned since. Not sure why it does that. This is rain water off of a tin roof.

PPM Meter is plenty fine for reading nutrient strengths. Not sure what nutrients you are using but I'd recommend getting something like General Hydroponics Flora *ova (site is censoring the word, begins with an N) Grow and Bloom, they are very simple to use. I'd also recommend a bottle of Advanced Nutrients pH Down. It is a stronger pH down than GH's version, meaning you'd need less and the bottle would last longer.

Those are the things I'd do to get the plant health back on track.

Thanks for the recomendation, I just can't bring myself to spend the dough on the commercialized stuff.

The mix I use is afordable. When mixing 200 gal at a time

Flora Nova would be 25x more expensive compared to homebrew nutes. For a small hydro setup its not a big deal as you dont get through a lot.

This is only one of 3 separate grow beds we have.