TDS is all I need to know? Seems to work for me...

dav.tomassini

New Member
Jul 16, 2017
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NL
Hi there,

I have moved 6 months ago from EI to PPS only because I was tired of big weekly water changes. My tank is 120 Liters, with medium/high plants load, with medium fish load, medium/high (PAR around 70 st the bottom) with adasoil (about 2 years old), RO water, KH2, Ph 6.2 ( 1.1 unit down when co2 is on) with dwarf baby tears carpet, AR mini and a few easier plants. Plants are all doing fine with no noticeable algae on plants or ricks
( I clean the glass weekly to remove an almist unnoticeable layer of algae that starts growing only on glasses). I have only dragon rock and lava rock, which I have soaked for days in ro water with unchanged TDS readings before using it in the aquarium. So, I assume I have no significant mineral leaches into my aquarium water that may affect the TDS readings.

I dose very, very lean counting litterally drops of some sulutions I mostly made. I dose every day the following (with double of the doses below plus 20 ppm. Ca, 10 ppm Mg and 10 ppm K after 50% water changes that I do once x month):
NO3 0.5 ppm
PO4 0.05 ppm
K 1 ppm
Profito Easylife 10 drops (this is 0.3 ml)
Fe DTPA 0.03 ppm 10 drops
Flourish trace 10 drops

The TDS reading after 50% water change and the addition of Ca, Mg and K is around 110 ppm.

The point is that the TDS reading does not change over weeks. It stays consistently there one or 2 ppm up or down.

I trim the plants in order to have always a similar plant mass. So they should consume the same nutrients over time.

Can I dare to draw the following conclusions:
- I have found a stable sweet-spot/ balance
- I may remain in the sweet-spot/ balance also if I further reduce water changes, just making sure to slightly increase or reduce over time my fertilization in order to keep the same TDS reading?

Thanks.

Cheesrs,
Davide
 

Allwissend

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Jun 20, 2016
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TDS, actually the device measures water Electrical Conductivity (EC) , is a sum parameter hence cannot say anything about the individual concentrations of ions in mixed solutions.
The water can have the same EC while K keeps accumulating and Mg keeps running lower and lower for example. Likely a lot of stuff are running very low thus starving the plants for the nutrients they need to growth.

EC is a bad at telling the concentration of organic substances.

sure i guess you can say you arrived in a sweet spot of having a TDS of 110. It's very similar with people doing everything they can to keep the pH at 7.00 or ORP at 357 mV . If that works for your setup then relax and enjoy.