# TDS discussion.



## plantnoobdude (15 Mar 2022)

I'd like to ask you guys what your tank tds is. and some relevant factors. 
1. How often do you change water and percent.
2. What is your dosing regime (ppm numbers per week)
3. What is your target calcium and magnesium levels.
4. What is your tap water tds (or just say you use RO if you do.)
5. How much does TDS rise throughout the week.
6. If you do use remineralised water have you tested the tds of the water with zero ferts and only calcium and magnesium.
7. what tds scale does your meter use
8. and lastly what is the tanks tds.
additional info:

my details.
1. once every two weeks, 50%
2. 8ppm No3 (urea), 0.8ppm Po4, 1.5ppm K+traces,
3. 18ppm Ca, 6ppm Mg.
4. RO
5. very little tds rise usually. maybe 2-5 ppm in two weeks. with heavy plant growth, tds can go down.
6. remineraliser water only is 65-70ppm TDS
7.  TDS-500
8. tds is 85ppm.
additional info: tank has new soil which is raising TDS a bit. 

cheers.


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## MichaelJ (15 Mar 2022)

These numbers are from just one of my densely planted low-tech tanks (the tank where I keep shrimps).

1. 40% weekly
2. Currently 15 ppm NO3, 4.6 ppm PO4, 20 ppm K
3. 28 ppm Ca  9 ppm Mg.
4. RO+DI - comes out at 2-3 ppm.
5. About 3-5 ppm.
6. I didn't measure with just the Ca & Mg, but with K2CO3, Ca Mg, NPK included (I frontload everything except traces for the week) it comes out at around ~125 ppm. (fairly close to my target if I add it all up). Depending on evaporation I may _cheat a bit on the scale_ and top off will pure RO water - that always shaves off a few ppm.'s as well.
7. 0-2000 ppm.  uS/cm conversion factor 0.5
8. 125 - 130 ppm.

Cheers,
Michael


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## Hanuman (16 Mar 2022)

I am not concerned about TDS so don't measure it often but will answer your questions for my main tank:
1. ~70% weekly.
2. 



3. Ca 20ppm - Mg 6ppm
4. Tap water TDS varies widely so I use RO for my tanks.
5. Don't really check TDS rise. All I know is that when I measured a few weeks ago it was ~220 at weeks end just before WC.
6. No because I remineralise straight in-tank. Not the best thing to do butI have no space for a 110 liter bucket to remin water to stand. This said considering my RO is at 9ppm and I am adding 20ppm of Ca + 6.67ppm of Mg + 74ppm of SO4 that would equate to 109ppm.
7. COM-80 – HM Digital - (TDS Range: 0 – 5000 ppm (0.5 Scale) ; 0-8560 ppm (0.7 Scale))
8. As of now 205ppm. That's 2 days prior WC.


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## John q (16 Mar 2022)

Currently.

1. About 50% weekly.
2. 7ppm No3, 2.27ppm Po4, 8.42 K, 1.35 Mg + traces. 50% Macro's front loaded with wc.
3.  Ca 8.6ppm -  Mg 2.18ppm.
4. Tap water 65ppm
5.  45 ~ 55 ppm 
6. ~
7. Tds range 0 ~ 2000 ppm or uS/cm, no idea of conversion factor. 
8. 180 ppm, water changed on Sunday. 

Good stock of fish.


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## bazz (16 Mar 2022)

1. 56% weekly
2. 20ppm NO3 = 7.47 KNO3 + 3.72 Urea +  8.8 CaNO3 from Remin, 3ppm PO4 = KH2PO4, 25ppm K = 4.71 KNO3 + 1.23 KH2PO4 + 5.97 KSO4 + 5.97 KCl + 7.11 KCO3 from Remin, 0.4ppm Fe from APF Traces
3. 22.89ppm Ca, 6.88ppm Mg = 4.79 dGH 0.94 dKH (hopefully)
4. 357ppm but use RO ~9ppm
5. 73ppm
6. 120ppm
7. ppm (cheap TDS Pen) but occasionally correlate with a decent conductivity meter
8. 160 - 193

No stems in this tank.


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## plantnoobdude (16 Mar 2022)

thanks for all the replies, very interesting to see these numbers. in different types of tanks.


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