TDS ( total dissolved solids ) means just that. Even though your TDS reads OK for the maturity of the plant you are growing it does not tell you if the combination of ingredients are correct. That is why you change your solution every two weeks because there is no way of telling how off you are with only a TDS meter.
Ok so yall say this over and over... I am new to hydroponics. I started in jan this year. I tested my Ph 3 times now. It was always near 6.7 I added Ph down and it goes right back up... I have never used a tds meter, when my water gets low I replace it and throw in some of Rons hydro food. I haven't changed my water once. My garden is gorgeous. I have already ate many spinach and bibb lettuce salads. I have zucchinis out the wazoo and 40 or 50 tomatos getting ready to ripen. I think all you need is some water and some hydro solution. Keep yer bells and whistles, they aint needed.
Ttucker406@aol.com