Thanks for the link and info Johnsonsmith. A couple of other questions though. Do you suggest an EC for tomatoes? The link you sent says flowering and fruiting tomatoes need a lot of phosphorus and potassium. My General Hydroponics "floramato" doesn't list potassium as an ingredient. In fact none of the fertilizers I have list potassium. I do have some human KCl (potassium chloride) tablets, should I add one of those?

Never mind, I see that Potash is potassium. I'd still like to know what EC level you use for tomatoes, year round indoors, flowering/fruiting?

Thanks

I wouldn't take anything "Johnsonsmith123" says here, or posts on his website seriously. He's just an "advanced nutrients" salesman trying to post his website links in forums pretending to be helpful. His goal is to get you to visit his website, and buy their products (as well as, as many people they can). That's what all their information is geared for. They also want to try and boost their search engine rankings, which is done by the posting of as many links to their website as they can on other websites (like in forums). Their constant forum SPAMMING, as well as the "F" rating from the Better Business Bureau (BBB) shows their company has a huge lack of morals and ethics running thought the company. It also clearly shows they have no concern for customer service. Their lack of ethics stems from the owner of advanced nutrients (the guy they call big mike). With someone that has such a lack of ethics running the company, the entire company will never have any company ethics.

I only use artificial light to start my seedlings, but I would recommend using the highest wattage high pressure sodium or metal halide light you can if you want to grow tomatoes indoors.
For the EC, anywhere between 2.0 and 3.0 is fine, watch the plant for signs of deficiency. Tomatoes are pretty tough when it comes to the fertilizer, you can let it go pretty high and they will be ok.
There is no real vegetative/flowering nutrients for tomatoes, the nutrients don't make them flower, their age does. As they grow tomatoes, they do need more potassium, but most nutrients have enough already and you don't need to add anything extra.

Thanks Homehydro, I was wondering why Johnsonsmith's answer was so generic and didn't really answer any question I asked.
And thanks sdgrower for the info. I've been trying to grow tomaotoes at ec of 3.6 and got sour tomatoes. I recently pushed it up to 4.4 and they completely stopped growing and the tomatoes are turning black on the bottom and no new flowers for about two weeks now. So obviously a lower EC like 2 to 3 must be better. On another post, 1.8 or so was recommended. I think I'll slowly titrate down and see what happens. I am using a 600watt HPS light now. I have a 1000 watt combined HPS and MH but I'm not ready yet to spend that much on electricity (at least until I've tried adjusting the EC.
Thanks again

I grow tomatoes both in a green house and full on indoor with 100% artificial light. I can't say either way works better than the other. Obviously being outside gives you more room and lower electricity bills, but depending on how cold it gets in the winter you still have to run heat. But the full indoor is all my own personal weirdo stuff. I mix my own nutrients for the tomatoes. Otherwise I just buy the cheapest stuff you can get because it doesn't make that big of a difference as long as it's formulated appropriately for tomatoes. Remember your basically paying to truck around water. It's a huge rip off. GenHydro had a product called FloraMato for a while, which was a dry mix but it was hard to dissolve and work with, so we switched to Flora Duo, which works well.

What are you using the tomatoes for? That would dictate the type. Is this for sale to restaurants? Are you eating them or do they have to be shipped and stored?