Yellowing between the veins on middle leaves of an indica in soil is more often a pH problem than a real deficiency, since nutrients get locked out above about 7.0 or below 6.0. Testing runoff rather than just the water going in tells you what the roots are sitting in. Charts showing which elements lock out at each pH point, with photos of the leaf symptoms, are hosted on https://kushindicaseeds.com in the troubleshooting area. Adding more feed to fix a lockout only makes the salt buildup worse.