AverageWhiteBloke
Member
May be a stupid question which I'm over complicating but why not. Am I right in thinking that if I have a 50 ltr tank with a TDS of 127 which loses about 4 ltrs of water per week and I top this water off with rain water with a TDS of 12 that I've raised the TDS by 12 divided by the 50 ltrs 0.24?
Reason I ask is I'm trying to get a rough idea of fert build up in a low tech, I seem to be getting some consistent results using a rule of third with this tank and good plant growth. I.E I change a third of the water weekly and dose a third of EI levels.
Everything in my tank is now inert after removing some seiryu stone and changing for a lump of lava rock. At the start of the week right after the WC before any dosing my TDS is around 127 (This is lowering weekly due to the rainwater water changes but measured from start of week then the end) The Difference between the start and the end is consistently 17 ppm, I add 27ppm of ferts through the course of the week which means that the net result is 10ppm of "something" but topping off would only account for a 0.24 change? Meaning the rest is a mixture of bio and food waste and whatever ferts are unused?
Reason I ask is I'm trying to get a rough idea of fert build up in a low tech, I seem to be getting some consistent results using a rule of third with this tank and good plant growth. I.E I change a third of the water weekly and dose a third of EI levels.
Everything in my tank is now inert after removing some seiryu stone and changing for a lump of lava rock. At the start of the week right after the WC before any dosing my TDS is around 127 (This is lowering weekly due to the rainwater water changes but measured from start of week then the end) The Difference between the start and the end is consistently 17 ppm, I add 27ppm of ferts through the course of the week which means that the net result is 10ppm of "something" but topping off would only account for a 0.24 change? Meaning the rest is a mixture of bio and food waste and whatever ferts are unused?