2 grams of Cal nit per gal gives a nice calcium base supply and a nice week always usable nitrogen supply. If you are just topping off and adding nothing else using Cal nit at 2 grams a gal should work well in flower or veg
Adjust your feed strength down like 20 % in strength if your plants are not eating and drinking more water. Your in a much better situation if your plants are eating all the nutrients and leaving a half gallon or gallon behind.
Not sure about your case, but if you need calcium you could also consider CaSO4, calcium sulfate.
That's assuming it's dissolved in water. Unfortunately, CaS04 is only slightly soluble in water and a poor choice for hydroponics.
If your using Jacks then part B is calcium nitrate. Just up your feed and you will have more calcium.
Solubility is high enough to supply all calcium. A saturated solution of CaSO4 (2,4 g/L) has 500 ppm of Ca. Twice as much as a cannabis plant could ever want.
You should top off with RO then check your EC after it has a while to mix in well. I grew about 50 rubbermaid tubs in DWC over the years from '01 and would only top up every 3 days then check ppm and add small amounts of nutes using syringes to bring it back up to my target range. Could do a whole grow from clone to chop without ever changing nutes using RO water with AN 3-part nutes. Never having to check pH was a real nice bonus.
When he said drinking more and EC rising I thought it sounded like a Coco DTW grow. I realise I was mistaken now.
And here we got one spreading false information
