There is a device called Nanny easyponic, I haven't used it . Luck!

When you water your plants in your garden with 3.0 EC it's essentially getting "diluted" by any remaining salts, moisture, soil and losing some to runoff. Not to mention salts that aren't in contact with roots that the plant will need to go find with new roots and/or rely on microbes to search them out for uptake. Basically, there are a lot of buffers in soil which make it different than when roots are completely immersed in a 3.0 EC solution and getting constant access and exposure to that concentration of salts.

It's best to separate plants that are not very salt tolerant, like lettuce, from salt tolerant plant like tomatoes. Not only for making it easier to run different concentrations but more importantly they will have different nutrient needs. But...if you're going to grow these together you should be able to run 1.2 - 1.5 EC for everything and get decent results. Higher EC doesn't necessarily equate to better or faster growth. Many times it's the opposite. My tomatoes, currently fruiting, are running at 1.3 EC.

mitchnc, if your peppers and cukes never went beyond seed leaves at 600ppm I'd look at other factors besides your nute concentration for the stunted growth. They should have had no issues at all at 600ppm.

Could ambient temperature have been a factor? The water was heated at 70F, but we had unusually cold weather that had my non-insulated basement at about 45 degrees.

Most definitely.

Thanks for all your answers!

I won't be growing lettuce and tomato together because it seems to be one of the worst combination on hydroponic. I thought fogponic would be an easy aeroponic system (and as long as your setup is running good, it should be) but I've found there is a downside: Fogger only give up to 500 ppm, so not every plant would be sastified with such system.

Now I'm thinking about making a fogponic system for low requirement plants like lettuce and herbs. I'll be working on a nft system with water pump and fogger to grow strawberry, pepper and tomatoes with the same water tank with EC at 2.0. That system would prevent failure with both being active. I hope a single fogger won't heat that much the system however... Anyone experiment with cheap fogger ?

I put a high class fogger in the tote. No significant sign of fogger based root growth. I'm not willing to buy an expensive minute by minute timer for it. It does make a lot of fog.

What is a high class fogger ?
What system are you using and what plant are you growing ?

I got it at House of Hydro and just plopped it in there. It makes plenty of fog. I wasn't willing to pay the long bucks for a high powered minute by minute timer. So my attempt was very half-baked. If I were serious I would put it in a separate fog chamber and get a fancy timer.

Lettuce. Aquarium bubblers at the bottom. They seem to help a lot.

I can see that the small bottles of GH Flora nutes won't go very far, so I'm thinking of switching to dry fertilizer and mixing myself. I was going to go with 4-18-38, and instead of CalMag I was going to use calcium nitrate and epsom salts.

Is this a good plan?

Well I'm running on jack's hydro and their calcium formula (we can't get the calcium nitrate alone in Canada so that was the perfect deal), it seems fine. Can't compare to anything else because I haven't tryed anything else. The only problem is dissolving it, you might want to prepare your solution a day before to make sure it is all dissolved. Much cheaper however, kinda got infinite nutrient supply ahah

I didn't try to make my own nutrient solution (I mean like a quantity per liter), but if anyone have a good gram per liter recipe, I'd really like to know about it!

Also, can I use transparent pump tubing for a NFT system since the water will always be moving ? It seems like these pipes are much cheaper than the black one (at least on ebay).

Edit: Don't forget to make an A/B solution (B is calcium nitrate and epson salt and A is everything else) so everything will be dissolved correctly :D

Everything I've seen uses clear/translucent tubing.
I'm going to cover all of my white bucket lids with duct tape, though, to be safe. I don't think I'm going to paint the buckets themselves. Chuckwagon seems to be doing fine with white buckets.

FYI duct tape isn't quite light proof. I used a combination of Foil, spray glue and electrical tape. Still have some pin holes. I think Chuck use hydroguard. There is another thread where hydroveggiegrow has a pic of his kratky setup and they're in clear mason jars and looking healthy. Go figure :-)

Edit

I've also heard that foil tape is light proof and works though it's expensive for what it is.

Wow, so it really take so little light to promote algae?

Foil would give the plants more light I guess.

I seem to be ok with keeping algae at bay it's the brown slime I'm fighting with. Apparently that doesn't need light. Bennies are helping though.

I thought brown slime WAS algae. Geez...I have a lot to learn.

True slime is bacteria. Although algae can sometimes feel slimy and seem gelatinous.

When it comes to mist or fog based aeroponics, the nutrient concentration needs to be considerably weaker than normal, typically 10%-25% .