Using distilled water to lower gh & kh?

[toffee]

The GH and KH in my 20g tank are both 300ppm, can I lower them by swapping 1/2g of tank water with distilled water every day? 1 gal a day for 10 days will be 10 g or 50% of the tank.

Opinions?

 

[dudley]

What is the GH and KH of your untreated tap water?

What substrate are you using? Any other buffers or additives you are using?

 

[dougall]

Your mathematics don't quite add up . It will take longer than you expect as when you change water you are changing less hardness than you think . The second day you change water, the hardness will be less than 300ppm, so the hardness doesn't decrease directly, but on a curve. It would be best to allow longer and to test the water to see how you are doing

And it depends why you are lowering the hardness too. Lots of fish may not need the change.

Ultimately, I assume you are planning to do water changes with half tap and half distilled water?

 

[toffee]

What is the GH and KH of your untreated tap water?

What substrate are you using? Any other buffers or additives you are using?

Crushed granite gravel, no buffers.

the tap water:
ph: 7.8
total alkalinity: 240
carbonate: 120
general hardness: 500

 

[toffee]

Your mathematics don't quite add up . It will take longer than you expect as when you change water you are changing less hardness than you think . The second day you change water, the hardness will be less than 300ppm, so the hardness doesn't decrease directly, but on a curve. It would be best to allow longer and to test the water to see how you are doing

And it depends why you are lowering the hardness too. Lots of fish may not need the change.

Ultimately, I assume you are planning to do water changes with half tap and half distilled water?

Yes!

 

[dougall]

How is your tap water? Does it match the tap?

If not, think about your water change schedule... Do you let water evaporate and just top off with tap water most of the time?

 

[toffee]

How is your tap water? Does it match the tap?

If not, think about your water change schedule... Do you let water evaporate and just top off with tap water most of the time?

yes

 

[Pinkey]

I'm a little late to the party but this is probably not resolved so here we go. My tap water is >400ppm and I add water to replace evaporation on a nearly daily basis. The hardness gets really hard after a few months of this (I rarely do water changes because all the other parameters are pristine). I did some research on what the problems for my fish might be. I'm not keeping discus or anything so I can just expect to have challenges breeding (which I don't do so it doesn't matter). Eventually other problems are likely to present themselves. Is there a specific trouble you're experiencing because your water is too hard or could you let it ride? Maybe maintaining 300ppm is a walk in the park but it becomes a ton of work to drop to 200 and maybe there isn't much to gain.

 

[FreshyFresh]

Sorry if I missed it, but why are you trying to adjust your KH and GH to something different?

 

[toffee]

I'm a little late to the party but this is probably not resolved so here we go. My tap water is >400ppm and I add water to replace evaporation on a nearly daily basis. The hardness gets really hard after a few months of this (I rarely do water changes because all the other parameters are pristine). I did some research on what the problems for my fish might be. I'm not keeping discus or anything so I can just expect to have challenges breeding (which I don't do so it doesn't matter). Eventually other problems are likely to present themselves. Is there a specific trouble you're experiencing because your water is too hard or could you let it ride? Maybe maintaining 300ppm is a walk in the park but it becomes a ton of work to drop to 200 and maybe there isn't much to gain.

I did replace 6 gal of tank water with distilled water, Kh dropped to 80ppm, Ph to 7.2 but Gh remains around 250ppm. In view of the low Kh, I stopped swapping. Like you, I seldom do water changes.

This is the tank, pic taken 2 days ago, current stock:
8 x harlequin rasbora
3 x albino corydora
1 x dwarf gourami
1 x bristlenose pleco
1 x hillstream loach
anubias
Java fern Windelow
Swards