Help needed

Hi all, growing some autos in ecothrive Coco under 20/4 light schedule.my first time using Coco as usually use soil. The plant in question is coming up to week 4 and pistols have started showing. I'm using shogun Coco nutes and tap water left out for 24 hours prior. Over the last week I have been giving 1.5ml of A and 1.5ml of B (per litre) and watering until around 10% run off. Once mixed has a ppm of 550-600 and I have been phing down to 5.8/5.9. Yesterday I noticed some slight tip burn so reduced feed down to 1.2ml of a+b per litre. Today I have noticed that leaves are starting to yellow(very early stages that isn't that noticeable) but wanted to rectify it asap. So checked run off and was a whopping 6.8ph ppm 320. Not sure if I did the right thing, but I decided to flush it to reduce the pH and then gave a light feed at the end. It is in a 4l pot and have had to put nearly 50l of 5.8 pH water through it just to get it down to 6.1.. I very new to coco so unsure why the pH is rising so much.i know I've probably done more harm then good by doing this but it appeared it could be lock out as the leaves are yellowing yet tips burnt. My first thought was to up the feed but then the burnt tips indicate not to and I thought maybe bringing the Coco pH down may help

Here is the plant in question.

I'm not familiar with your nutes, but 550 ppm is not too high.
Are you feeding every day to substantial run off?
Do you ever give plain water?
No need to check the pH or ppm's of your run off as long as you feed daily with correct pH and ppm........I never check my run off for anything.
With 4 ltr pots you should be feeding multiple times a day........at least twice.
Your flushing probably messed up the calcium and magnesium in the coco.
It's not necessary to let your water sit out for 24 hours.

Sounds like you are doing a lot right tbh. You have to consider all factors of your grow. Tempature, light intensity, humidity etc. If any of these are off it will affect all the other factors. Hope this makes sense. Make sure that your light intensity is not too high. 600ish par right now should be about maximum. Later in flower you can bump it up some. As to why your ph is rising probably you have hard water with a lot of calcium. What is the ppm of the water before nutes? Anything over 200ppm is hard water. Might want to invest in a cheap ro system. Also might ph to 5.5 and see if that helps. Good luck.

Southside112 said:

Sounds like you are doing a lot right tbh. You have to consider all factors of your grow. Tempature, light intensity, humidity etc. If any of these are off it will affect all the other factors. Hope this makes sense. Make sure that your light intensity is not too high. 600ish par right now should be about maximum. Later in flower you can bump it up some. As to why your ph is rising probably you have hard water with a lot of calcium. What is the ppm of the water before nutes? Anything over 200ppm is hard water. Might want to invest in a cheap ro system. Also might ph to 5.5 and see if that helps. Good luck.

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Straight from tap my ppm is 239. Haven't thought of light intensity. I'm running a 200w led at 50%. I'll have to check the pr ratings

Greenthumbgrower1986 said:

Straight from tap my ppm is 239. Haven't thought of light intensity. I'm running a 200w led at 50%. I'll have to check the pr ratings

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Hard water with high calcium for sure.

You're starving your plants. You don't need to test the run off PH in coco. You only have to check the run off EC. You should never flush your plants in coco. You should feed until the last day. Until the day of harvest. Increase the A & B to 1.6ml per liter. Your plants are starving. If the ppm is going in at 550-600 and coming out at 320 then that means she is starving. You don't have a lockout. You are just underfeeding. If your run off EC comes out lower than the input EC then that means she is eating all of the nutrients you are putting in which indicates that you are not feeding enough.