How to reduce GH and TDS without increasing the pH by too much?

[Francis247]

Hi all,

I just did a check on my water parameter and found that my GH is 11 and TDS is around 230.
Is there any way to reduce the GH and TDS without increasing the pH by too much?
Please advise. Thank you.

[wongce]

WC using distilled water?

[Suzerolt]

Agree, GH is a measure of calcium and magnesium.
Best way to lower it is to replace some tank water with distilled or RO/DI water.

[Francis247]

I see...
Is there any type of filter media that can help?
What is the best way to get RO/RI water?

[Urban Aquaria]

I guess you meant reducing GH and TDS without decreasing pH by too much? Higher GH and TDS tends to harden water and create higher pH, while lower GH and TDS tends to be soften water and hence lower pH.

Anyways, doing water changes with lower GH and lower TDS water (can be de-chlorinated tap water, our local tap water tends to be relatively low in GH and TDS) can help gradually reduce those parameters through dilution... or you can use RO/DI water (which has zero GH and TDS) to reduce the parameters even faster.

For RO/DI water, you can buy bottles of distilled water from supermarket... or buy a RO/DI unit to produce your own distilled water.

[Suzerolt]

Singapore tap water has a GH ~ 5 and TDS around 70, of course defendant on your location. Are you adding salts to your tank?

I've read about an API product that reduces GH. But would suggest that water change is a better option.
http://www.apifishcare.com/product.php?id=550




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[Francis247]

May I know where to buy RO unit in Singapore?

[Urban Aquaria]

May I know where to buy RO unit in Singapore?

You can check at the more popular LFS, or just check at online sites... here is a RO/DI unit commonly used amongst aquarists:

http://www.aquamarin.com.sg/products...?productid=379

There are other brands and models, so just shop around to compare their prices and features.

Note that the RO/DI cartridges have a limited lifespan, hence they have to be changed after processing a certain amount of water, so the replacement cartridges will be part of your ongoing running costs (how often you need to change the cartridges would depend on the TDS and quality of your source tap water).

[Francis247]

Hi UA,

Thanks for your reply.
Just an update. Gotten some Cation Resin and now the GH dropped. But TDS still high...

[Urban Aquaria]

Just an update. Gotten some Cation Resin and now the GH dropped. But TDS still high...

The resin is probably more specialized in absorbing the minerals that contribute to GH, but TDS contains alot of other things which are not absorbed... most likely its excess dissolved organic waste and matter which is not being used by plants, so its just slowly accumulating in the water. Water changes will help to remove those. Adding more fast growing plants may also help (must have sufficient light for them to grow and absorb the excess nutrients too).

Your TDS of 230 isn't considered too high, a water change or two will easily reduce it. Most people usually keep their levels around 100-200.

[Francis247]

The resin is probably more specialized in absorbing the minerals that contribute to GH, but TDS contains alot of other things which are not absorbed... most likely its excess dissolved organic waste and matter which is not being used by plants, so its just slowly accumulating in the water. Water changes will help to remove those. Adding more fast growing plants may also help (must have sufficient light for them to grow and absorb the excess nutrients too).

Your TDS of 230 isn't considered too high, a water change or two will easily reduce it. Most people usually keep their levels around 100-200.

Thanks for your reply UA.
Just did a water change using distilled water.
The current parameter,
KH - 3
GH - 4
PH - 7.1
TDS- 214