I gt new ppm pen. The oxypot rez has drooped 1.5 litre ppm 565 and the Ph was 5.3. I added 1.5 from 5 litre of made up nutes (10mil a+b aqua veg) then waited 30 min then phed to 5.8. And the brummie bubler rez drooped 3 liter and ppm 605 so I added the remaining 3 litres of made up nutes. Didn't need to adjust Ph as it was 5.8.