Now my cherry tomato seedling is doing the same thing.

The cherry tomato seedling is probably doing it from peer pressure. Ha!

But on a serious note, your ppm is a little high for seedlings and every time you add pH down you're raising the salt level. Those pepper seedlings don't even have real leaves yet, still the cotyledon (seed leaves). They're still young to be putting in there. Do you have roots coming out of the cube yet? How wet is the rockwool staying?

As a general rule, I don't put anything in until I at least have the first set of real leaves and some decent roots, at least enough that I know they will be working their way out of the net cup within a couple days if in a small net cup and if in a net pot lid I want the roots to be touching the bottom.

No roots coming out. Rockwool is damp but not soaked.

I didn't realize that it was too early for them. I thought I was doing them a favor getting them into the system.

From now on I will wait until they have a set of leaves and roots.

Everything else seems to be doing well.
Thanks as always!

Is it ok to top water them with a bit of solution until the roots break out in to the solution?

I've transplanted early before successfully but water level, moisture if you're using something like rock wool, light intensity and nute strength more easily can become issues when the plants are young and fragile. It's just best to wait.

How much light do seedlings need? I installed a cheap fluorescent light under my kitchen counter to hopefully grow some Kratky lettuce. It's only 15 watts. I'm wondering if that's enough to get seedlings up to speed if they're close to the light.

http://www.lowes.com/pd_76376-1390-GU9721-GROW-WH-I___?productId=1260219&pl=1&Ntt=grow+light

The light intensity reference was referring to when you go from one light setup to another like seedlings under some T8 and then move them into a system with a 1000w hps, for example. Plants will develop leaves based on the light they have been getting and when moved under something more intense it can affect them sometimes in a very bad way. The guys at my local hydro shop moved a sunflower plant that had been under a 450w MH to a 750w LED they were testing. The LED was a good 2ft above the plant and you would think would be fine but it fried the plant in a couple days. Not from heat but light. Leaves curled up and died. The plant recovered under that same LED but the leaves were like half the size they had been under the MH. Anyway, I am sure that's not what is going on with you seedlings but that's what I was referring to. It's kind of like when you harden off plants to go outside and get them used to temp and changes gradually. Plants are very reactive.

To answer you question, seedlings need a lot of light so they don't get leggy. I use dual 4 ft 32w t8s for mine placed about a inch above the seedlings. Sometimes I'll use my T5s but you gotta keep them farther away since they put off more heat. That light you put the link to is not much light. Problem with the question of will it work or is it enough is that you could propagate under that and grow lettuce but it'll be slow going and you'll have leggy seedlings. So it'll work, just not real well. Look at this way, plants grow in direct proportion to the amount of light they get.

Ok...from now on I'll make sure my seedlings are under the same lights that they'll be transplanted to.

I really want to hang a serious light on the ceiling and be done with it.

I don't know if you need to go that far. It's in extreme cases that I've seen that issue and it usually involves a big intensity difference although the LED thing I described left me and the guys at the hydro store scratching our heads. It wasn't that much difference, at least by wattage. I move from my t8 for propagation to the t5 which are 4X the strength all the time with no problems.

the curling is normal when they are just starting out.. i will say that 650ppm is way too high for peppers seedlings. what is the ppm of plain water? start peppers around 150-200ppm and once they are mature, 550-600ppm seems to be the sweet spot. peppers don't require a lot of fertilizer/nitrogen. tomatoes on the other hand will be happy with higher ppm (around 800-900)