Calcium deficiency can be provoked by Magnesium excess, even when there is plenty of Ca around, you need to check out this possibility. You are using the percents on the label which makes perfect sense to a logical person, but industry enjoys exaggerating and confusing, or something like that. The N-P-K numbers are only for elements in the first case of N. P is "expressed as P2O5" and K as "K20" which inflates the phosphorus and potassium by adding some hypothetical oxygen that actually isn't in your hydroponic fertilizer. Don't ask why. No sense on reinventing the wheel, here's what Wikipedia has to say about this: The factors for converting from P2O5 and K2O values to their respective P and K elemental values are as follows: P2O5 consists of 56.4% oxygen and 43.6% elemental phosphorus. The percentage (mass fraction) of elemental phosphorus is 43.6% so elemental P = 0.436 x P2O5 K2O consists of 17% oxygen and 83% elemental potassium. The percentage (mass fraction) of elemental potassium is 83% so elemental K = 0.83 x K2O Nitrogen values represent actual nitrogen content so these numbers do not need to be converted. To convert 2.73% nitrogen to express as ppm when dissolved in water, just specify how much 2.73% fertilizer is in how much water. For 300 *grams* in 17 gallons, the ppms are estimated for the working solution by the weight of nitrogen/ weight of water. A gallon is 3785 grams. In this case 8.19g/64,345g = 0.0001273 To convert fractional part to parts per milliom (ppm) instead of percent, multiply by 1,000,000 instead of 100. That comes out to 127 ppm for N. P and K need to be adjusted by the factors mentioned to get the pure element and then calculated the same way. That's all I did. The absolute percentages in the fertilizer as you have them are not as relevant as their ratio to each other since a more concentrated fertilizer uses less weight of fertilizer to get to the same point. I do suspect that you have a nutrient problem though and my thinking base on the limited info is that there may be too much magnesium in there locking out potassium. That I got from the generalitities you've mentioned. However the symptoms as discussed sound more like nitrogen deficiency and there are no more limbs to go out on without real quantitative info and this will all make sense as you get into it more. For example, if the plants with more light are growing faster, they may have a greater nutrient demand and the plant may do what yours are doing by sapping nutrients from old growth to support and favor younger growth and reproductive tissue (tomatoes!). The last picture seems to be far more pronounced and not limited to the older growth though, not sure, the tones seem to be saturated in yellow (maybe on another monitor is shows up better but I have a cheapo monitor that freaks washing out with saturating colors) making it harder...

I believe that there is a big misunderstanding here, as you are lumping tomato yellow leaf-curl begomovirus and tomato yellow leaf curl virus into the same thing. These are two different viruses. Ms. Pfaff is correct: there are no varieties available to home or commercial gardeners for Tomato Yellow Leaf-Curl Begomovirus (or to those of us that study pathology, Sarania). This is a disease that was first found in about 2002/2003 and is a 'newer' strain of the original Tomato Yellow Leaf Curl Virus. It is a small problem for a large grower, but I highly doubt a home gardener would have it. As Ms. Pfaff mentioned, using resistant varieties for other diseases would keep plants healthy enough to combat Sarania if it should strike. What I think you guys are talking about in this thread and getting rather confused on is there good old Tomato Yellow Leaf-Curl Virus. This has been around since forever and any seed company that carries hybrid tomatoes has a tomato that will be resistant to it. The varieties listed above are good examples. The way that Tomato Yellow Leaf-Curl Virus morfed into Toamto Yellow Leaf-Curl Begomovirus is linked to insecticide resistance in the whitefly. The white fly acts as a vector to transmit the disease from plant to plant through it's sucking mouth parts. Initially, farmers treated their viruses by taking out the flies. As the flies built resistance, the virus transcribed into a more virulent form. Thus, it is now a begomovirus. I applaude Ms. Pfaff for being up on her information. GMO varieties for Bego-resistance have only been on the market for a couple years. Quentin, PhD in Plant Pathology and Tomato Breeder working on non-GMO Bego-resistant tomato varieties

I wouldn't worry that much about the curled leaves. They curkl when it's too hot, too cool, too wet and too dry and when there's a heavy fruit burden. If they curl over into a tube like structure, then look for aphids. Spots on the leaves in your area suggest one or more of the four most common foliage diseases, Early Blight ( A.solani) and Septoria Leaf Spot being fungal and Bacterial Speck and Bacterial Spot being bacterial/ There is no tomato spray that is effective against both fungal and bacterial foliage diseases. The fungal ones do progress faster and I might suggest you consider using Ortho Garden Disease Control for the fungal ones. But perhaps it would be best for you to go to the Tomato Pest and Disease Forum, link at the top of this page and find the thread titled Problem Solver #2 and look at the posts for links to sites that post good pictures. One of the best is TAMU. Then see if you can match up what you see with a picture. Carolyn

How are your plants doing? Please post followup images.