Have a 5g bucket, but only fill up about 4g.. Doing DWC with GH Line of nutes. The directions say Maintenance Dose: Add one spoonful for every 200 US gallons (760 L) every two weeks...So how much for 4 gallons then??? And I want this bc Im worried about my rez temps going above 72... Temps of rez have been between 68-71.5.