Water people - Question about TDS and Nitrates
More and more I have been seeing questions about the TDS on people's tanks as people are trying to dx problems. So - I decided to read up on TDS and buy a TDS meter. This morning I measured my water straight from the well, out of my RO filter, sink, and distilled.
Well - 648 (liquid rock I believe that is called)
RO - 41
Sink - 664
Distilled - 1
Well - 7.6
RO - 7.0
Sink - 7.8
Distilled - 6.7
So - I then tested my tanks. This is where my question comes up.
I have been experimenting with the different tank types and seeing how the plants and fish do in the different environments.
75 gallon planted tank: Running for 1+ year - ADA Amazonian substrate, heavily planted, drift wood, some rocks. LED lights (75% - 8 hours) 2 Eheim Canister Filters, water changes every other week with top offs during the week. Fertilizer once a week - Flourish. 10-12 Tiger Barbs, 10 Gold Barbs, 6 Corys, 5 Amano Shrimp
20 gallon planted tank: Running 3 years - Gravel, root tabs, medium planted, drift wood. T5 (10 hours) HOB filter, water changes every couple months with top offs. 8 Cherry Barbs and a clown pleco. Very heathy fish and 3 of the barbs were born in that tank.
10 gallon planted tank: Running 6 months - Dirted with black diamond blasting sand cap, medium planted, lots of floating water lettuce. T5 (10 hours) Internal filter, water changes every other week. 2 GBRs, 3 pygmy cories.
5 gallon planted tank: Running 9 months - Dirted with black diamond blasting sand cap, heavily planted, water lettuce. T5 (8 hours with siesta) No filter, quarterly water changes. 1 Betta
75 gallon: TDS 951, PH 7.6, Nitrates 10
20 gallon: TDS 105, PH 7.4, Nitrates 80
10 gallon: TDS 715, PH 7.2, Nitrates 5
5 gallon: TDS 765, PH 7.7, Nitrates 0
I cannot figure out what is going on with the 20 gallon. Why is the TDS so much lower than the rest of the tanks? I expected the Nitrates to be high due to less water changes but I also expected the TDS to be higher.
The 75 gallon makes sense, more heavily stocked, higher TDS and Nitrates make sense.
Off to do my water changes....