TDS keeps raising

[Narto Sunarno]

Hi folks.

In my 64L aquarium, I'm using many Seiryu stones and soil is Prodibio Aquagrowth, not too thick, around 3-4 cm. Started it on late July 2018.

During cyling, TDS was around 200. I had 3 siamese algae eaters just after cycling ended. Over the time I keep adding more plants.

Just 1 week ago, I put the fishes (10 cherry barbs, 5 mountain minnows, 3 small killifishes) and 40 horned nerite snails.
I'm limiting my feeding, a few crushed Tetrabits in the morning.

Fertilizer is a ready mix liquid Macro+ (0.02ml / liter) every Monday&Thursday and a ready mix liquid Micro+ (0.01ml / liter) every Sunday after WC and Tuesday.

My problem is the TDS keep raising. WC weekly 30% using RO water (TDS<10). Before last WC on Sunday, TDS was 395, then just after WC, TDS was 240. And now Tuesday morning it went up to 363 again. I'm expecting it will be around 400 on Sunday.

I have a hunch that those Seiryu may leech some minerals into water. I haven't tested the soil yet. Or you guys suspected other things that could raise the TDS?

How to control TDS?
Do I have to change all Seiryu into more inert stones (which one), or can I just put epoxy over those stones?

Thanks folks.

Best Regards,
NRT

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[rebel]

Yes It's the Sieryu. It 'may' improve as the rocks get a biofilm on them. The only way to reduce it would be to do water changes.

Dragon stone is inert if you are looking for another stone.

 

[Konsa]

Hi
Your fertiliser is adding to the TDS too as are your fish.Its normal to get that sort of increase in a well fertilised and stocked tank.U dont need to control TDS unless U are breeding some finicky softwater shrimp or fish.There is no need to overcomplicate your life with that sort of things.Just keep good water quality with waterchanges and enjoy your tank.
Regards Konsa

 

[tam]

Be careful changing with pure RO without remineralising. Although it makes your TDS appear to lower/stay more under control, the stuff that is making up your TDS might be changing dramatically. Potentially, as an extreme example, depending what is being added from other sources, you could end up with 0 GH / 0 KH and a high TDS made up from other stuff.

It would probably be better to do larger changes with water remineralised back to where you want it e.g. 200.