might be too much nitrogen. I believe that makes the leaves curl under.

I run a bit different setup for tomatoes. When the plant is between 4-12" tall, I setup the PPM to 500-1000 PPM, then when it is between 12-24" tall it goes to 1500-2000 PPM, and from 12-36" it goes to 2000-2500 PPM and over 36" I keep it around 2500-3000 PPM depending on the size of the plant and amount of fruit.

I have a cherry tomato plant that is 5 feet tall and I setup its solution to 2750 PPM, and in five days it drops to around 1600 PPM. I only add fresh water to it during that time.

My target PH in my solution is 6.3, so very close to yours. Also, your PH fluctuation's seem to remind me of another Hydroponic Solution brand, but it was the opposite on the change. It would start out at 6.3, and then drop to 5.8 every 12 hours with me adding PH up every day to bring it back up to 6.3.

I run a one part, two phase solution from General Hydroponics now called Hydro Nova. I no longer get the huge PH swings in my solution on my tomato plants. All I do is add water now, and it changes the PH back to 6.3. I also let my water sit in a bucket getting aeration for 12 hours before using it. They add Chlorine and Fluoride to the water where I live which artificially raises the PH 1.0.

When my grow room reaches temps above 88 degrees, the tomato plant leaves will curl under during the hot parts. However, overnight the plant recovers and the leaves are back to normal. I have a lot of air moving in my grow room as I have 3 large commercial fans running at any given time.

When I water my plants, I water them with straight water through the media, not to the tank, This fresh water helps to leach out the salts that can build up in your media.

Do not know if any of this helps you, but it is what I do, and it seems to work pretty well.

The solution is changed out 1 time per week when it is young, and every 5 days when fruiting heavily.

Hey guys did some searching on the web and I found out that tomato leaf curl can be caused by cold and rainy periods. The description suit my plant to so I'm guessing it's because of my grow room temps.

I think my PH problem would have to do with the reservoir being so small I have heard it tends to swing quite fast when your reservoir volume is small. Might also be the nutrient I am using I'm sure if I got a nutrient specifically for tomato's all the nutrients would be taken up more evenly thus giving a more stable PH.

Might try adding some cal/mag to the nutrient seeing tomato's seem to like that.

Cheers

Fil

I think you've got it figured out. Bigger reservoirs are always good, until it comes time to change them so keep that in mind. It can be a pain to find the balance between more solution to buffer against swings and less waste when you switch out the solution.

Calcium is particularly important for tomatoes, since not having enough is what causes blossom end rot.