DWC major issues, someone please help me salvage this baby

[VLRevolution]

I'm at day 21 flower. I have had this kind of issue almost all troughout the veg til today and i am out of ideas what to do.

Current settings:

*Ph 5.5 (Ph keeps going down fast even after multiple tries to pump it to 6.5). Prior to this week I was using 50/50 tap water / RO with added epsom salt and then the PH was more stable @ 6-6.5 range. This week took out epsom salt to test if it made a difference. Not really.

*Ppm 880

*Temps 24C

*Humidity 50%

*Using MegaCrop with some added epsom salt.

*Using LED-s and DWC

*Base water 50/50% RO/Tap that comes to 100ppm (my tap water is 200ppm)

What i have tried so far:

*Using different nutrients

*Increasing Calcium with Canna Mono Ca

*Increasing Magnesium with epson salt

*Increasing both Calcium and Magnesium with AN Calmag

*Foliar feeding with AN Calmag

*Foliar feeding with epson salt.

*Lower ppm (gradually building it up)

*Higher ppm

*Flushing

*Using tap water as a base(200ppm)

*Using RO water for base(0ppm)



Just 2 days ago bought a more powerful air pump because seems like roots problem. So far it has not made a big difference.

Current theory:

Maybe this strain is very sensible to nutes and this is just nute burn? The strain is Matterhorn CBG and it is known to be unstable genetics. Should I try flush it for 24 hours then put 500-600ppm? Few weeks ago we did a flush and it stopped the spotting but it started to get worse again in 3-4 days after resuming to 600-700ppm.



Does anyone have any other ideas what should i do or try. When i first noticed this kind of problem at the early stages of the veg i though it could be magnesium or calcium issue so i started experimenting with both them, but i havnt made anything better, sometimes maybe even worse. Could my water just contain something bad? I noticed my water filters are really old and I am replacing them today. Could this be the root of the issue or not likely?

 

[TanzanianMagic]

*Ph 5.5 (Ph keeps going down fast even after multiple tries to pump it to 6.5). Prior to this week I was using 50/50 tap water / RO with added epsom salt and then the PH was more stable @ 6-6.5 range. This week took out epsom salt to test if it made a difference. Not really.

The deficiency (not lockout) is showing up as a calcium deficiency - see the shotgun pattern of the damage on the leaf. I'm presuming it's indoor and there are no insects visible under a microscope.

I think the thing to try is just 100% tapwater.

The 50/50 tapwater/RO may still not have enough absorbable calcium and magnesium.

Also the pH may be dropping because the Epsom Salt or MgSO4 is both magnesium and sulfur. If the plant is taking up the magnesium and not the sulfur, the unabsorbed sulfur would pull down the pH.

 

[bigpeter]

That certainly looks like calcium deficiency 3-4 ml of calmag in a litre of water sprayed over the tops and undersides of leaves. Followed by a second treatment 6 days later. Foliar feeding gets nutrients into the plant much quicker than via roots. Spray when temperature isn't too high. For most this is just as lights are coming on, less spray evaporates, and there's more time for it penetrate into the leaf. If you spray at this time, raise lights up high when spraying. Another good time to spray leaves is just as lights go off. It wont cure the damaged leaves but all new growth will be will healthy.

 

[VLRevolution]

We swapped out the dirty filter in the water line and this changes ppm of our tap water from 200>160.
Our plan of action is now:
We did a Foliar spray (3ml/1L) AN Sensi Cal-Mag) just before lights went out today.
We also did a res change and are currently flushing for the next 12 hours with 160 tap water PHed to 5.9 (altogether 180ppm).
Then tomorrow when lights come on we are going to do a res change with the following paramterers:
we take our 160 ppm tap water and add cal-mag until 250ppm. Then add another 350ppm worth of mega crop 1 part. This brings the total to 600ppm. PH to 5.8. We are making this solution tonight and let it sit overnight.
Fingers crossed that it will bounce back now! I will keep you guys updated.