45cm new tank low kH but high gH. What could be the cause?

[bonjour2]

Hi folks,

I have recently started a new planted tank ( 45 cm). The specs are as follow:

-Age: 1.5 months old ( waited 1 month for cycling before planting. TC plants planted only into 1.5 weeks old)
-Soil: Ammazonia Ver 2.0
-Rock : Dragon stone
-Plants: Monte Carlo , rotala rotundifolia, rotala h'ra , rotala macrandra mini red

-NH3: 0ppm ( API test kit)
-Nitrate: 0 - 5ppm ( API test kit)
-PO4: 0.5mg/l ( salifert f/w test kit)
-kH : 3 ( API test kit)
-gH : 10 ( Sera and Colombo test kit)
-PH : 7
-CO2 : 6 hrs at 2 bubbles per second
-Light : 7 hrs daily
-Water change: 30 to 50% per week

I have been trying to bring down the GH but could not establish the cause of high GH in tank. The tapwater GH reading at my side ( west ) is 3 dH. I figured out it cannot be the soil which is suppose to create a acidic and soft environment, nor the layer of lava rocks underneath and the dragon stones which should be inert.The only remaining thing I suspect is the filter media in my filter ( OASE filtro 100). I am using the OF 3dm filter media, and read online it is a form of mineral based medium. Would this be a possibility and how do I test to ascertain the root cause? Am thinking of replacing the filter medium with sintered glass for a try.

[genki89]

Do you dose any fert?

With your tank planted and co2, i strongly believe that you have dose fert if not, most plant will start to melt/turn yellow due to lack of nutrients with so much co2 and lights.

And is your test kit liquid or test strip? Test strip is not as accurate as liquid test kit.

Although GH do not directly relate to TDS, with a GH level of 10, your TDS should be over easily 200. You might need to test tour TDS as well.


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[bonjour2]

Hi, I did a reset of my tank with lava rock + bacter 100 + ADA superclear and ADA soil , and invested in the TDS meter.

The tank is into its first month... and currently the paramters are

-NH3: 0ppm ( API test kit)
-Nitrate:5ppm ( API test kit)
-PO4: 0.5mg/l ( salifert f/w test kit)
-kH : 2 ( API test kit)
-gH : 5 ( Colombo test kit)
-PH : 7
-CO2 : 6 hrs at 2 bubbles per second
-Light : 7 hrs daily
-Water change: 30 to 50% per week

TDS = 53 for tap water and 170 for aquarium water.

Using 2hr aquarist fert at 1 pump ( 2.5 ml) every 2 days + 1 extra dose of potassium.

I am monitoring the tank parameters now...hopefully everything is stable this time ; )