Posted this on reddit but having no luck on responses Novice hydro grower on my first attempt. Cucumbers are about 4-5 weeks old started from seed. I'm using Botanicare Pure Blend Pro (Grow) in ~30 gallons reservoir w/large airstone Top feed drip 15mins on / 15min off then 15 mins on / 2hrs off during the night PPMs started ~500 around week 1; now are ~1600 pH was about 6.3 the first couple of weeks & was lowered to 5.9 a week ago Added ~65 ml of CalMag about 4-5 days ago after researching thinking it was a magnesium deficiency temps in the tent are 77-80F degrees during the day & never lower than 65 at night 18/6 light cycle under a Spider Farmer 4000 LED I have 5 fans inside the tent plus an 8" carbon filter w/fan The first plant to start showing signs of deficiency is on the far right, followed by the middle plant about a week later and now I'm starting to see the same happening to the last plant on the far left. The leaves have been crispy & dry feeling since the start. I've never grown cucumbers before so I'm not sure if that's normal for them. Very easily cracked if touched. In this same tent I have 4 DWC buckets with 2 bell peppers, 1 jalepeno & 1 tomato. I also have an aerogarden I'm using for seedlings with more peppers & tomatoes. None of these are exhibiting the same symptoms as the cucumbers & are using the same nutrients & water but they are around 800-900 ppms as they are about two weeks behind the cucumbers. I also haven't added any CalMag to the buckets. It's worth noting that my house came with a water softener installed when I bought it so all of my tap water runs through that first. However, I'm not leaning towards this being the issue since only the cucumbers are exhibiting the yellowing. Bell peppers, jalepeno & tomato plants are healthy & green. My tap water is around 100 ppm 7.4 pH. Also worth noting that the first week was spent trying to dial in feeding times. I'm still not convinced I have the right feeding cycle but this is what I've tried. 1st few days I was running the system 24/7 but I felt like that was too much After that I went to 15min on / 1hr off for a few days which felt like too little then finally settled on 15 min on / 15 min off which has been running for about 2-3 weeks they are drinking roughly 5 gallons every few days The closest pictures of deficiencies I found that matched mine were for magnesium but adding the CalMag 4-5 days ago hasn't made too much of difference, at least yet. I'm trying my best to research but can't find the solution. Overall it seems like cucumbers are much darker normally too. Can someone help identify what might be the problem? Thanks in advance!
thanks for the reply! I can easily dilute the res since its 70 gal but I only maintain 30. I did have a problem with algae early on that required me to drain the res & clean it out I've since added hydroton in the bottom of the tray enough to where the water level is always covered along with the roots. I do add 30ml of 34% hydrogen peroxide one per week to the res. my biggest fear is the softened water (which does use salt) is causing high salt levels which is blocking out key nutrients like K but since my aerogardens & DWC bucket plants aren't showing the same signs as the cucumbers I'm hoping that's not the case. I'll have to look into RO water but I don't have access to a filtration system for that. Cheapest one I've seen was $550 on amazon for an undersink style. Unfortunately the whole house softener came with it when I bought it so it would require a plumber to take out I'll dilute the res to 1000 ppm for now and see how they do