KH drops from 5 to <1 overnight

[jojo3367]

Hi Guys,

I’m struggling to understand why my KH drops and it’s not steady.

I use RO water and then Seachem Alkaline buffer to bring KH to 5 and Seachem Equilibrium to bring GH to 7.

I topped up KH to 5 yesterday as I noticed it was really low and today is the same low <1.

I still haven’t added plants or fish as I am running dark start method and want to get water parameters right.

Tank has around 60-65l of water and only Tropical soil and dragon stones.

Please help how do I get my KH steady.

Thanks
Mike


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[bazz]

and only Tropical soil

Is that Tropica Soil? If so it will be sucking up the KH.

I use RO water and then Seachem Alkaline buffer to bring KH to 5

Just out of interest, why would you want to increase it to 5 dKH?

 

[jojo3367]

Is that Tropica Soil? If so it will be sucking up the KH.

Just out of interest, why would you want to increase it to 5 dKH?

Yeah, it is Tropica soil. Is this KH sucking going to stop eventually?

I read on 2hraquarist that KH between 2 and 7 is perfect for most plants and with dosing ratio 5dKH comes up easiest for my tank.


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[bazz]

Yeah, it is Tropica soil. Is this KH sucking going to stop eventually?

Yes it will once the substrate reaches equilibrium with the general conditions of the water column.

I read on 2hraquarist that KH between 2 and 7 is perfect for most plants and with dosing ratio 5dKH comes up easiest for my tank.

It is obviously entirely up to you, but most of our aquatic plants do well around 4 dGH and 1 dKH. This will also suit most of the soft water fish we keep i.e. Tetras and Rasboras etc. Most Snails and Neocaridinas will require higher values than this but Ramshorn Snails and Caridina Shrimp will be fine. It just seems a bit of a waste to me to be loading RO water back up again.

 

[jojo3367]

Yes it will once the substrate reaches equilibrium with the general conditions of the water column.

This was good point. I’m just reading about the same problem people are having.

It is obviously entirely up to you, but most of our aquatic plants do well around 4 dGH and 1 dKH. This will also suit most of the soft water fish we keep i.e. Tetras and Rasboras etc. Most Snails and Neocaridinas will require higher values than this but Ramshorn Snails and Caridina Shrimp will be fine. It just seems a bit of a waste to me to be loading RO water back up again.

I was concerned about PH stability and wanted bit higher KH and KH that is good for 97% of plants.

I’m planning to add these, do you think 1dKH will be fine until soil reaches equilibrium?

Also, I bought RO unit as my tap water is really hard, don’t remember exact numbers now, but over 10 KH and GH.

Thanks


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[Andy Pierce]

I’m struggling to understand why my KH drops and it’s not steady.

It's because you have an active substrate, Tropica Soil, that is messing with your water chemistry. If you want to fully control your water chemistry you need an inert substrate like sand or gravel.

 

[jojo3367]

It's because you have an active substrate, Tropica Soil, that is messing with your water chemistry. If you want to fully control your water chemistry you need an inert substrate like sand or gravel.

Yeah, I was just made aware, but as many folks use active substrate with ADA range being top choice for some, how do we manage KH then?

If I top up KH every day an my substrate eat so much to the point where it can’t anymore will it then start releasing it back to the water and I’ll end up with KH raising constantly or should then just by steady?


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[dw1305]

Hi all,
What the others have said. I'll link some threads in when I can access a PC.

At UKAPS we haven't got anything sell and we will really try to give you good advice.

I was concerned about PH stability

You can actually just ignore pH, pH can only be stable in very highly buffered scenarios. It is relevant if you keep Lake Tanganyika cichlids or marines, but not otherwise.

People who write about "pH stability" either don't understand water chemistry, or want to sell you a product, or both. @Andy Pierce is a scientist, and doesn't want to sell you a product, but he really understands water chemistry

While we are on the subject of lack of honesty, I have a bit of an issue with Seachem, and I can't recommend their products.

and wanted bit higher KH and KH that is good for 97% of plants

It just isn't necessarily true, in fact it is untrue. I'm actually a botanist by training and it is a gross simplification of a infinitely variable situation.

Also, I bought RO unit as my tap water is really hard, don’t remember exact numbers now, but over 10 KH and GH

Perfect, just add a small volume of that, say 10%, and that is your RO remineralised. It doesn't cost you anything and provides 1 : 1 dGH : dKH.

Cheers Darrel

 

[bazz]

I was concerned about PH stability and wanted bit higher KH and KH that is good for 97% of plants.

Do not worry about pH stability and KH values with an active substrate, and 97% of plants will be fine (there are a few exceptions).

I’m planning to add these, do you think 1dKH will be fine until soil reaches equilibrium?

Yes, they will be alright. People use these active substrates to create (as best as possible) ideal conditions to start up a tank. The buffering capacity duration will vary between 3 - 6 months approx, by which time the microbes will have taken control.
There are quite a few tanks on this forum which are running at 0 dKH (although regular water changes are required using this method), I run at 0.5 dKH.

If I top up KH every day an my substrate eat so much to the point where it can’t anymore will it then start releasing it back to the water and I’ll end up with KH raising constantly or should then just by steady?

It will only go as high as what is generally in the water column. If you was to decide to lower the KH in the future then the process will be reversed.

Seachem Alkaline buffer to bring KH to 5 and Seachem Equilibrium to bring GH to 7.

It might just be me, but I would look into not using these products for the future. Off the top of my poor arithmetic head, it tells me you could possibly be adding 80ppm Potassium to your tank.
With the use of RO and the fact that you are obviously taking a deep interest, I would suggest downloading and familiarising yourself with the excellent IFC Aquarium Fertilizer Calculator which also has a built in Remin Calculator. You can also as suggested by Darrel, just add a percentage of tap water, ensuring your fertz contain a little Magnesium, if not, just add half a teaspoon of Epsom Salts to your water change RO water.