These plants are fantastic!It seems like when growing,there is always "something" else to buy.I have an oakton ph meter.I got it last year,I didn't replace the probe yet,and I am getting funky readings.When I test my water,it will say (ie...)5.8 and then after a couple of seconds it will flip to 2.5 and then it will alternater between 5.8 and 2.5.I am thinking that I may need to replace the probe....50.00!Have anyone else had this problem?This ro water seems to acidify the longer it sits.My plants are incredibly hungry and thirsty creatures.I added about 2 gallons of ro water since changing the res last week...bought my ppm down to a 150.So I added 150ppm cal-mag and some food which brought my ppm up to 530.When I change out the res on friday I will up the ppm to 700.Must get ready for work now