Does seachem flourish affect gh?

[ymk87]

Hi guys! Just a question here up for discussion. I've recently bought the api gh kh test kit and discovered that my tank water has a gh of 13 while my tap water is 3.

My tank is a planted tank and I do add ferts according the EI dosing. My plants and livestock are doing fine, in fact my rcs are breeding at the moment.

Would this gh of 13 be bad for my tank? What's the ideal gh range?

I did notice seachem flourish has calcium and magnesium in it. So I'm wondering if it has anything to do with the increase of gh.

Here's a pic of my tank:

uploadfromtaptalk1466000826468.jpg

[Urban Aquaria]

The amount of calcium and magnesium in Seachem Flourish are in very low trace amounts, usually not enough to accumulate such that it increases GH noticeably (unless you are massively overdosing it everyday). Any minerals in the ferts should be used up easily by the plants. I've used Flourish in my planted tanks and in some setups dose 3-4x more than recommended dosage due to higher densities of plants, yet the GH levels didn't increase.

Based on the photo of your tank, the GH increase is most likely due to those rocks. Those types of rocks are commonly known to release minerals over time. You can even see the white calcareous veins on the rocks themselves.

A higher GH level is usually okay for most hardy livestock as they can adapt to it if the changes are gradual. But it could sometimes be an issue for certain sensitive livestock like shrimps which may encounter molting difficulties at higher GH levels.

RCS are generally hardy and adaptable so they could adapt to the higher GH levels, but if you find that they are starting to die off due to molting issues, then you'll have to gradually reduce GH with water changes and consider removing or replacing those rocks.

[ymk87]

Thanks UA for the info! I didn't know my rocks could release minerals.. I have them in my set up for 6 months now

Don't think I can easily replace those rocks at the moment but I'll just observe and see how my livestock are doing. Or it could be an excuse to rescape lol

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[Urban Aquaria]

Yeah, those types rocks usually release minerals and raise GH slowly over a period of time, the changes are gradual. Its a common occurance in tanks that mainly use rocks as hardscape. The overall effect also depends alot on the ratio of rocks vs water volume too, so just have to factor it in.